Yes. Once installation is done like an XP machine would be. Linux can be up and ready with Office, media players and so forth within an hour.
Games are not all well supported, ID games are very well supported. I play Q3, Q4 and Doom.
My Q3 was compiled from source code I edited for my CPU, Athlon AMD 64bit 3200+. I edited the source to allow us to rail through walls, instant weapon switch, stronger kickback, rocket jumps don't hurt, instant guantlet kills. If you put all that together, with a bit of damage balancing you can get 2 kinds of players. Campers and crazy people. My flatmate camps and shoots me through walls, I rocket jump to where he is at and guantlet him. Amazing game.
Anyway, DX10 requires Vista at the moment, so use Vista for games. Use Linux for media, browsing and anything else. I run a virtual machine when I need something specific to Windows, the virtual machine image is win98 and is 8 years old now.