I don't think you would see a difference between using DVI -> DVI and a DVI -> HDMI cable at a resolution of 720P.
Do you/ will you have another need for the HDMI input, such as a cable box, or a stand-alone Blu-ray (or a stand-alone DVD with upconvert) that will require/use the HDMI input If so your choise is limited to the DVI -> DVI.
I believe you have Composite and S-video inputs also for other devices. Some video cards come with a DVI to HDMI adaptor. This is what I am using, Not the best solution but it was free with my Video card.
As I stated above, I'm using the DVI (w/converter) to HDMI. Waiting till I visit my son as he has several DVI -> HDMI cables laying around that he will give me.
My setup
Samsung T240HD HDTV Monitor Connected as follows:
Computer, Conneted to HDMI #1
Liteon DVD recorder (w/cable input) to Composite Video in
Indoor HD antenna connected to antenna in
Reason I'm using the computer connected to the Monitor HDMI input is that I have a Blu-ray recorder in my computer. Vista/video playback requires it, other wise I would have gone with DVI -> DVI
Smokin221 - His native resolution is as jaguarskx stated, 1366 by 768. The TV is 720P/1080i (no 1080P). I agree with jaguarskx that he will not see a difference between using DVI or HDMI.
My current monitor is 1920 x 1080 and is 1080P. With my old 22" TV (720P), there was no difference, Not sure with my new one, don't think I tried the DVI->DVI as internal Blu-ray Writer would not play a Blu-ray disk without using DVI->HDMI unless I wanted to install Anydvd (Which I have, and use when I boot in to XP.