as far as gaming and multimedia go, you're not going to get bleeding edge performance out of that machine. i have one of those exact models myself and it's one hell of a workhorse, but keep in mind that it's about 7-8 years old and has a 60mhz processor with no built in video card. you can get an "apple HPV" card to drive larger resolution monitors and add some cache chips (available from
www.outerworldcomputing.com) to increase performance a little bit, but other than being a good jukebox and running some older games, it's not going to compare to high end pcs (i hope that you did not pay more than about $20 for the machine).
it will run all of the games in bungie's classic pack or whatever they call it (abuse, marathon 1,2, and infinity), the origional escape velocity, the origional tomb raider, stuff like that (the extra cache and video card will increase performance a lot for these games).
while i've actually done video and audio editing on the machine, no recent media programs will run, you'll have to find old copies of avid videoshop 3 and stuff like that (and it will be slow).
it's a very cool machine and can do an amazing amount of stuff considering its age as well as being surprisingly upgradeable, but for the money you'd spend to max out it's upgrade options, you could probably buy a refurbished imac.
this site has every bit of info you could ever want on the 61xx line of machines (including info on connecting vga monitors)
http://www.kan.org/6100/