If you're rocking an LCD or plasma with at least 720p resolution, then sure.
If not, don't even bother wasting your time. You could try DivX, but if you're still using an old CRT, you're better off just sticking to a DVD player.
If you actually have an LCD or plasma capable of playing this stuff, you’ll need a decent computer—think dual-core at minimum—and a slightly better graphics card with a DVI or, ideally, an HDMI port. If your card only has DVI, you'll need to grab a DVI-to-HDMI cable, making sure it's long enough to reach from your PC to the TV.
On the flip side, there are little gadgets like this one
http://www.wdc.com/en/products/Products.asp?DriveID=735 where you can just plug in an external hard drive and watch everything through a tiny device connected via HDMI. In that scenario, you don't even need a computer to handle the playback.