best format to put dvd - avi, mpeg, wmv??

[smur1701]

What is the best format that looks great on DVDs primarily. VCD and SVCD maybe, but I prefer DVD.
Should I convert avi's, mpgs, wmv, etc? What software is good?
Sometimes things seem a but too grainy/pixelated when on DVD but fine in medai player. I Have Roxio 6 to make the DVD. I also have Ulead Video Studio but maybe I am doing somethign worng or it stinks.
Any help would be greatly appreciated.
Thanks.

[setarip]

What is your source material?

[smur1701]

Well, I get some HQ wmv files (300K i think?), and some other formats. My father send me things with is digital video recorder at times. Problem is he is lost when it comes to computers, digital video, etc. How do I find out what quality I am getting other than just seeing an extension on the file? I am new to the recording game honestly. I work in the IT field, but this DV recording I have only starting to toy with.
Sorry I dont have more info.