I started using Media Portal late last year on an old second hand rundown computer with a hauppuage 150card, the idea was to make a pvr on the cheep as i had just got a dvd/hdd recorder and that did not work out too well.
after my demands grew so did the budget

, but i think im done (well i hope im done as i have spent far more than i wanted too

)
my system consists of a back end server, and a front end client with a 40" 1080p samsung, and 5.1 audio, a 1.3Tib raid 5, raid for storage.
Back end server:
TV Cards:
2x Hauppauge WinTV-HVR4000
1x HAUPPAUGE WinTV PVR150
HDD:
160gig time shift drive
260gig rec drive
40gig os drive
Mainboard/CPU:
im not sure

, some amd thing
1gig ram
Front end:
40"1080p Samsung
5.1 amp + speakers
SILVERSTONE LASCALA SST-LC17 (Black) Case
Asus P5S-MX SE mobo
Asus Blu-ray player,
intel core 2 duo cpu,
nVidia 8600GT video card,
1gig ram
40gig hdd,
S/PDIF out for audio (with ac3 filter)
MCE IR with Logitech Harmony 525 