I played many years with MythTV and XMBC, and now on our new home and after buying a TV, I finally decided to switch to XBMC. I will explain all my choices for those of you who want to build your own media center:

HARDWARE

1. Plasma TV 42″ Full HD Panasonic TX42S20: about 630 eur (but I got it by only 460 eur!). Plasma TV’s are now quite cheap and they offer a great image quality (much, much better than any LCD, believe me).
2. Logitech X-540 5.1 speakers: 94 eur, very affordable. They are an old model but what I like of this is that they are wall mountable. They have only one sound input, so I connected them to the computer and the TV audio output with the Line Input of the computer (with a RCA to mini-jack cable, 2 eur). I needed to make some extension cables with RCA connectors to reach the speakers positions. Theoretically these speakers haven’t enough watts for the room,  but it has great sound quality and makes up for it.
3. My OLD computer, an Athlon 2 GHz with an ATI Radeon 9550 (with DVI output) and a SB Live 5.1. I needed also a HDMI cable (10 eur) and a DVI to HDMI converter (15 eur).  Curiously this “slow” computer is able to play video to a FullHD 1920×1050 output. I’m planning to get a Home-PC case, at the moment the PC is in a corner of the room.
4. An Iomega external USB Hard Disk of 1 TB: 95 eur. My old computer hadn’t enough disk space for music & movies. I could have bought a Multimedia Disk, but XBMC is much more pretty and you can also configure it for gaming.
5. A T-Visto wireless keyboard with touchpad: 30 eur. I could had a a remote TV-like but finally I preferred a complete keyboard.

Total, about 900 eur without the computer.

SOFTWARE

For many years I used MythTV with a TV-tuner card on my computer, but I hadn’t a TV. There are only two features of MythTV not avaiable on XBMC: TV tuning and TV recording: having a TV I need no more the tuning, and I was not using the TV recording (there is nothing enough interesting on TV).

XBMC is a very cool media center available for Windows, Linux and Mac. I installed it over a Debian (because I’m a Linux Fan) but is easy to install on any OS. Is skinnable and has many plugins to add funcionality. Now I am using the default Confluence skin and the Launcher plugin for my games (Performous, Stepmania…) and Emulators (Mame, Mess…). This required some simple bash scripting to create all the launcher config.

Ok, this is a very funny hobby and I spent lots of hours choosing an configuring but the result is very good!