Some three years ago, we used to have a Windows Mediacenter for use with our beamer. Worked like a charm, but I had to abandon it, unfortunately. I always missed some of it's features, most dominantly the ability to pause live TV and also the easy way in which you select and configure shows to record them. I am sorry to say that Mediaportal nor MythTV can beat the userexperience and ease of use.
Anyway, after years of doubt we bought some components and I build a new mediacenter. Here are some pictures:
The system is based on an black Antec Fusion HTPC case. The motherboard is a Gigabyte nForce 630i based motherboard with Geforce 7100 video chipset featuring VGA, DVI and HDMI output. Unfortunately no coaxial digital audio output (for my speakerset), but little more to complain about. For now, there's only one Hauppauge PVR-150 card in the system. The on-board firewire will be used to connect to connect a FloppyDTV DVB-C card. This is about the only DVB-C card that integrates into Vista Mediacenter.
Update: Here's a (Dutch) videoreview and an article about this card.
Complemented with 2GB memory, a 500GB Samsung Spinpoint SATA HDD and an Intel dual-core e2180 (2x2000Mhz, 2x512KB, Conroe-L), this system isn't exactly the fastest you can get. But with a total price of just over 400 Euros (and a Vista license), I think it is dirt cheap. And above all, it is very silent, almost no noise when it's turned on. It will also go into S3 standby mode automaticly, without any fans or LEDs disturbing a good night sleep. Of course it will turn itself on when it needs to record or download updates for the guide. It sure beats the alternative, being an Xbox 360 (Elite), which makes an awfull lot of noise and needs an existing Vista Mediacenter PC to get it's content from.