First build. Budget. Media Centric

Hi, I've been lurking around the forums for quite a while now and I finally decided to join since I'm building a new system.

Well basically I just spent about 250 on:
C2Q Q6600 (I'm not sure what stepping it is, nor do I know how to find out )
Intel DG33TL Motherboard
and Vista Home Premium (I'm unsure whether I'm gonna use it or XP Pro)
as part of Intel Retail's Edge program.

Basically I want to spend 300-500 on the rest of the parts. I already have a Maxtor 120GB sata I can temporarily use but thats it.

In order of priority, I think I'm going to use this build for:
1.Media (Playback, Converting videos for MP3 players, DVD burning)
2.These particular Applications: Firefox, Office, Photoshop CS3 and maybe other art programs
3.Mediocre Gaming (I plan to add a GFX card in a 1-3 months, maybe a HD3870)


So yeah, this will be my first build ever. I don't plan on overclocking it cause I want a PC that is only faster than my old desktop (AMD64 3800+, 2GB-4x512 ddr 3200, Raptor 74GB, 7600GT) Even so, I might want to give it a go later on since I just want to try it out. Haha. I'm also considering maybe just selling the bundle I got and get a E8400 and a Gigabyte p35ds3l. Should I just keep the q6600 and dg33tl since I got it a good price? I also have no idea what case nor PSU I am getting. I really want the Antec 900 but its too pricey for me. (Maybe if I can find it for 70)
I'm getting 2GB of ram for sure. 2 sticks of 1GB DDR2 PC2-6400. Maybe a TV tuner as well.

Well I'm very budget oriented so any help would be really appreciated