If you have a lot of 8mm's and are willing to spend some money, having a company do it is well worth it. remember, when you are doing the conversion yourself, you have to do it in real time, so a 2 hr tape will mean you have to watch 2hrs.
If you are planning on editing, and the camera has firewire, you can import direct to windows and edit down the footage, then convert to dvd. I have done this, and edited tapes from 2hrs of footage to about 25min, so i could fit more on a dvd.