I think I might get a 6800 GT. Do you guys this will be fine to last two years or more? I will upgrade my motherboard, CPU, etc. next year or so.
Well... here's the deal. If you're planning to upgrade your MB in the next year then you're going to have to upgrade your video card as well -- buying a non PCI-Express board at this point is questionable. Buying one a year or more from now is just foolish. So take that into consideration.
If I wanted to buy a card right now that would last ~2 years then the 6800GT would be a good choice IMO. The 6600GT is a much better value IMO, but I'm not sure how it'll do a couple years from now -- particularly with only 128MB (and if you want 256, get the 6800GT; it's the same price).
My Antec PSU 400 watts will not be enough for upgrade.
I disagree completely. That PSU is more than adequate to the task -- even with the 3 HDs (ack, a Deathstar!) and 2 optical drives. The 5V line on that PSU is very strong, and while the 12V line could be better, it's quite good. I have an Antec 350W PSU supplying power to my server -- 4 HDs, an optical drive, and a Athlon 1400 (not
an XP, so higher power usage). I also have a 350W PSU powering my gaming rig -- Athlon64 3k, 1G memory, 2 HDs, DVD burner, and 6800GT. As long as you buy a quality PSU (and you did) it's unlikely you'll ever need >400W unless you run a huge RAID array in the box.
No suggestions on the tuner though -- check www.avforums.com and the various tech sites that are assembling HTPCs right now.