I've played my good share of games, WoW included, it does lag like hell, however, not that bad, 800x600? Cmon, I run my raids at 1920x1080, I do have to shut down a lot of addons though, as those are what cause the lag I think...
I think the most unoptimized game I've played this far, has to be Cryostasis, it's a complete waste of time, you can't get it to run well even at the lowest possible settings. Crysis, I think the main problem was all the foliage, the excessive amount of trees to cover up the fact it wasn't that pretty.
I know of one game that I played Anarchy Online, 2 years ago, that game was unoptimized, and now it's taken a complete turnaround, back then at 1600x1200 I'd lag all over the place, now at 1920x1080, not even a hiccup. Everquest 2 is pretty unoptimized, it doesn't look that great, but it's impossible to get 60FPS, at least for my card at extreme detail.
Finally, I'd have to add, I think the BEST optimized game I've played, is Prototype, that thing just does NOT lag, no matter your settings. I think the whole unoptimized thing is as someone said though, it's more of a problem of crappy ports from console.
*fanboy inc* Anything ported by Microsoft, usually works perfectly.