I dont have a 3450, but I have a 360 and a Strong desktop that Ive run MCE and now Vistas MCE on it.
Setup is easy enough, when extending to 360, its slow, pain in the butt cuz of limited video format compatibility, yes their are 3rd party workarounds, but again an significant inconvenience.
Its been awhile since I used XP-MCE, the vista version is nicer although still buggy and prone to serious lockups.
In the end I just purchased a long vga cable, optical audio, and ir remote for pc and pumped it through my home theater for an easier, stabler, more responsive, less hassle experience. That being cheaper that just adding an extra pc strictly for home theater usage.