Dell came out with the new Zino HD.  It's a small profile computer made specifically for HTPC.  You can get it as low as $230, or make it as beefy as $600+. Looks wise, it's pretty similar to a Mac Mini .

I would go with the Tech package + 4GB RAM upgrade.  With the Dell's "8 Days of Deals", the price comes out to $562 - $104 = $458.

• Windows 7 Home Premium
• AMD Athlon X2 3250e
• ATI Radeon HD 4330
• 4GB DDR2 RAM
• 250 GB Hard Drive (though I have extra hard drives for more storage)
• 8X DVD+/- RW Drive