I'm no fan of Windows Vista, but I absolutely love Windows Media Center (which comes baked into most versions of the operating system). It turns your PC into a full-fledged DVR, one that supports multiple TV tuners, requires no TiVo-like subscription fees, and pairs very nicely with HDTVs.
Hewlett-Packard has a pretty killer deal on the Pavilion Slimline s3300t, a compact but feature-packed media center with a surprise inside: a Blu-ray/HD DVD combo drive. That's right: for $749.99, less than the price of a hybrid high-def DVD player, you can get an entire media center PC.
I'll let you peruse the full specs for yourself, but suffice it to say, this is a really well-equipped system: dual-core processor, 500GB hard drive, 256MB graphics card with HDMI out. I recommend spending an extra $80 on the optional TV tuner, which supports both over-the-air HD and analog cable/satellite connections.
To get this deal, you need to follow the configuration options outlined at Deals2Buy. Don't worry if the totals seems off; everything comes out right at the end. The discount coupon that lops $300 off the price expires February 16. I have to say, I'm giving serious consideration to replacing my old media center with this powerhouse.