Maybe the best example of how HTPC application's prerequisites are different from desktop ones was my battle with various audio players. For many months I've struggled with XMMS, only because I was using it on my desktop computer for quite a while and it still seems to be de facto music player of everyone I knew. Unfortunately, while perfect in audio formats support, XMMS is absolutely the last audio player you should consider for music playback on your HTPC: it can't be maximized to fullscreen, can't open complete folders etc. So I gave a chance to application that was long in shadow of XMMS on my desktop - Amarok - and I've discovered a whole new world :)
Yes, Amarok is an eye candy application. Yes, it uses lost of system resources. No, it does not support all the obscure audio formats as XMMS. But it does implement file browser and player in one application, can work in fullscreen and has very configurable user interface. After I've stripped all unnecessary GUI elements from it (not all, but most of them can be disabled), I've got myself an almost perfect HTPC music player. Visualizations are still an issue though, but I never said that its perfect :)
