Guild Wars-like or not, I wish there were some incredible free, modern (high end graphics) MMORPG for the Mac as well. The only free ones I've come across are really outdated, often with sprite graphics, and a community, I suspect, that's not as active as I'd like.
Closest I've come across to fulfilling both free and modern is WarHammer online. They have a "free" experience wherein you can play the trial free forever, but with enough limitations that you won't be able to experience the proper game. I'll be trying it soon enough anyways.
There is DOFUS. Again, free with real limitations. Gorgeous art direction, but I think there may not be (installed, haven't played yet) a controllable 3D camera, so it may feel technically outmoded in that sense.
If you're willing to Boot Camp or virtualize (with free or paid apps) or Cider, obviously there's hundreds of free Windows MMORPGS at your beckoning. Here's, however, a great list I happened across last week:
http://www.freemmostation.com/2010/02/top-10-free-to-play-mmorpg-games.html Several of them look very interesting, and even attractive. For now, I'm trying #1 on the list as the art direction appeals to me, on a Windows 7 system with an integrated graphics card. Makes me wonder why free-to-play MMORPG developers don't port their games to Mac. Seems the Mac demographic and modest GPU demands of virtually all free MMORPGs make them a fairly ideal fit for porting to OSX.