I just got an Apple TV. Its awesome to be able to watch stuff from my little laptop on my bigger TV. Its so great.
I either watch it on the movie channels or I use Netflix/Redbox etc. I don't watch movies on my computer. Maybe when I get a better, faster computer I will.
If I'm in my room, I usually just watch them from my computer with 22" monitor, or I attach my laptop to my 32" tv if others are also watching with me.
I'm usually watch movies on dvd. Sometimes on pc too, but that's rare, because i don't find it entertaining to watch movies in small screen
I usually use 19" Samsung LCD with 2.1 Speakers to watch movies, but last months I bought 32" Samsung Full HD LCD and now I watch all movies on it with the help of Portable External HDD and i am loving it.
I've actually got my old busted PS2 hooked up to my 14" crt tv. The PS2 doesn't read any discs now (botched repair), but it's got SMS Media Player installed so I can just run media from USB drives
I watch my movies using PS3 on my Sony LED 3D tv. Its so great, that is when I even have time to watch movies lol.