From my perspective, if you have the same budget, why not just get a dedicated player and a netbook -- probably more or less the same cost as a HTPC. My definition of HTPC includes a 'nice case', which costs upwards of 10k (Antec Microfusion, Silverstone). This provides you with a remote which allows almost similar functionality as a standalone player (boot to media centre, remote control based operation).
What I don't like about HTPCs is the maintenance involved -- customisability / upgradeability goes side by side with configuration issues and installation problems. Case in point -- we tried setting up Vista 64 on an HTPC (not possible, at least as of a month or so before, we don't have the codecs for Vista 64), even Vista 32 required messing around with Codecs and wouldn't you rather spend that time watching movies?
What I do like about Media Centre is this:
http://www.mymovies.dk/ Man, this is what it's all about: movie cover art, movie info, artists, etc. all cross referenced and hypertexted so you can access all the information available froM IMDB.com. I think you have more options for this when it comes to HTPCs, with NMTs, it's pretty much basic to none.
If you don't go the 'nice case' route, and use your PC's for the occasional movie viewing, then it's pretty much good. Depends on your habits -- I just can't live without a remote so I need to have a VDU (video display unit) in front of my case (you can get them from IMON/soundgraph.com, we have a sample in store, but I particularly like the usb attached VDU+IR unit).
If you are an enthusiast, then no question about it: HTPC. Just that as I grow older, I find convenience to be more of a priority than being a hardcore PC user (mind you, I am a PC gamer, warhammer anyone?
). But NMTs and other similar appliances (NAS's for example) also have 'hacks' you can perform -- they're essentially simple computers anyway, and logging into them and reconfiguring them has it's own (geeky) appeal.
Of course, I'm also interested in getting a small form factor / low impact HD capable PC that will do both my torrents and some HD viewing, but that's more on the enthusiast side of me talking.