Best All Around Class for WvW

I'd recommend Ranger, for range, versatility, and support. They've got a decent bit of control, too.
The pets are fairly easy to ignore, although they're handy as a self-res and a dps boost.

Warriors are solid in WvW, but they suffer a little from being a jack of all trades. They don't have as much survivability as Guardians, nor as much ranged strength as Rangers, or the control/dps of Thieves. So it's easy to get smacked around by more specialized players.

Engineer's pretty great. Nade-spam does get a little tedious, but the profession's versatility, control, and perma-swift combine nicely. That mortar elite's a marvel in sieges, too.

I think it really depends if you're WvWing alone or with a party. For example, alone, Guardians and Elementalists both really aren't at their best, guardians because they're limited to mid-range at the furthest and generally aren't specced for damage, and elementalists for the lack of weapon-swap and general holy-crap-squishy-no-health-pool problem. In a party, though, both are absolutely fabulous.

Thanks for the responses so far, it's helping to get more input into my decision making process.

As to small/medium group vs solo vs zerg play, I do a fair mix of all of those really. I guess that's why I'm eyeing the warrior so much. Really my biggest concern with them is that rifle seems pretty boring. I may give engineer a whirl to see how much fun it is. I have to admit, it seems pretty engaging if nothing else. Plus my girlfriend has an 80 Engi, so I'd be able to give it a shot in WvW and not just the Heart of the Mists.

Alternatively, if anyone has non-glass cannon thief builds that work well in versatile settings I'd love to give it a shot (haven't found any so far, everyone on other forums seems to be building haste/backstab cheese).

Elementalists: Build a durable one, they aren't that glassy if you trait and gear properly. There are a few builds, but earth with bleeds is good for pvp. My roomie plays an Ele, and they don't die very often (they often take on multiple opponents), but they do need to move a lot and be proactive about things. You also need to be comfortable with kiting and a lot of movement in general. IE: the skill cap is high.

Mesmer: You live forever if you keep moving, but you are dead if you stop moving, and you will never be a high-damage class. Being able to get into range to get tokens is difficult for me personally, as that heavy and medium type (or a necro) over there is always finishing the enemy before I can get to them. (Coincidentally, I get all the enemy fire while said other medium or heavy or necro just gets to finish their enemy. On the other hand, I am almost never dead, so can at least roll from event to event. Not sure how I'll ever get enough tokens to get a legendary, though!

People always say melee isn't viable in WvW, but that's bupkis, I see warriors and guardians and thieves (daggerdagger) and such stomping around and they are always the guys somehow finishing off their opponents.

Most of the dead eles I see are the ones who just stand and pewpewlazors. That's a death sentence for anyone and eles players are so bad about this.

My roomie doesn't have much problems with damage as an ele, so it's deffo build, traits and playstyle that really matter.

I don't have a lot of experience on any class but thief in wvw.but I will say that I go into wvw without expectation since so far I am just learning by experience and not reading sites. What I find fun to do with my thief is just to harass people, spread conditions and pick off wounded people that try to leave the battle area. Since I tend to like survivable characters I also enjoy frustrating people who think all thieves are glass cannons - I once led three people a merry dance for about ten minutes - they got me, but all that time they were not attacking the keep and my guild mates were bringing in supply. It also amused me the energy expended on one very inconsequential thief run by a very carebear player.

that's actually exactly what i built my thief for. my traits are at 5/30/10/10/15 (though i may still tinker with it a bit in the future). for the actual selected traits, #3 and #11 are staples in the crit tree, swapping in #6, #9 and #10 in the 20 point slot as needed. i use #5 in shadow arts, to soak a bit of the initiative cost of cloak and dagger. i went with #1 in acrobatics, as i tend to do a lot of wile e. coyote style cliff diving in WvW, either when following the zerg, getting to the supply camp closest to the tower i'm defending, or just needing to escape from a group. i went with #4 in trickery to give my backstabs a bit of a boost. it also helps everything else out, since i'm keeping mobile and not many things can actually hit me if i'm not in front of them. i end up with a lot of initiative to burn, getting some back on my crits. and do my best work from behind (insert joke here). i can come in and get 9 stacks of bleeding in immediately with death blossom, 12 if a couple of the attack crit, which they usually do. with my gear set up, they hit for a decent amount. usually, though, i just use one or two, then cloak and dagger, then finish with a heartseeker or two.

setting his gear up was a bit expensive though. with the jewelry, i went with the emerald orichalcum pieces(power/precision/toughness) for the rings and earrings then popped an exquisite ruby(power/precision/crit damage) into all of them. for the amulet, i just went with the normal ruby orichalcum one, with the ruby jewel it came with. my boots and shoulderpads have precision/toughness/condition damage on them, while everything else is power/precision/crit damage. i went with 5 runes of the engineer, and 1 rune of the golemancer. in WvW, i use a shortbow primarily and drop cluster bombs onto people from the walls. it's a little slow, but if there are actually people helping you defend somewhere, it's easy enough to get a bunch of damage and kills in. i always keep a set dual daggers equipped everywhere, in case i need to switch to melee. (one with poer/precision/crit damge, the other with power/precision/condition damage.) i'm able to make use of all of the combat abilities, instead of just needing to spam heartseeker and cloak and dagger, or conversely death blossom. in dungeons, i swap out the bow for dual pistols, as they put out a bit more damage and range isn't as much of a factor. granted, they're only single target, and it's pretty much just spamming unload, but you're able to keep damage going while keeping mobile.

i don't specialize in any one area, but i'm also not pigeonholed into any one area either. i can do WvW, dungeons, and just roam around the world. i'm not popping 16k backstabs, but i'm also not dying to a strong breeze. i can scout pretty well on my own, and work better with a group in combat. some of the storyline missions were a bit rough though, but i think they've been toned down a bit since then. toward the end though, things became a whole lot easier. except for underwater combat. i tend to avoid it at all costs.

*wanders off to SPvP to give that a shot*

At this point (thanks to Sauerkraut's description) I've tried out an engineer, and am really loving it. I used a rifle build that was a little glass-cannony, so I'm worried how well it will end up working in WvW, but I guess it's risk I'm willing to take. The warrior is probably more what I'm looking for, but it just feels like playing hotkey whackamole.

Plus leather armor is ballin' in this game. Going to have to farm up a million billion karma to get the armor the human engineer wears at character creation.