We have LAN parties about twice a year - we usually play Warcraft III (mod games), FPS variants, etc.
I'm not a big fan of GuildWars. My Guildmates love it, though. I don't think it's this version of a mmorp that I dislike, but rather the whole concept of mmorp alltogether.
Just takes up too much time - I have a wife and a daughter, a boat, and am a huge college football fan.
I prefer real life.
Combat customization is where the game shines - you only get to choose eight powers to go into missions or group challenges out of the powers you gather while playing. That gives you a lot of tweaking and min/maxing possibilities, especially when coming up with personal combos and even more deadly team combos.
I tried it a while, but it wasn't my cup of tea. I'm playing City of Heroes/Villains now, and Masterminds are really fun to play. I'll always have a special place in my heart for Gemstone III, too, though I think I've finally kicked that habit (Gemstone IV helped with that - ick. Why, Simutronics, why?)
My 11 year old son is just getting into 'Rose Online' - www.roseon.com. It's free to play and doesn't require a software purchase. The graphics are more anime-like but he seems to enjoy it. And at this price(free), if he tires of it in a few months, who cares.