While HDMI connection is generally superior, there are a few quirks that have to be considered.
The biggest problem is that HDMI is a 'talking' connection. That is, it is not just DVD sending signal to TV, it is also TV and DVD exchanging various info. With an analog connection like component (the red-green-blue triple video cable), source component just sends the signal out in whatever format you tell it, leaving it up to user to assure thaere is something on the other end of the cable capable of using that signal.
HDMI, on the other hand, is "smart". The TV will tell the source that it is actually there and it is actually on, and what signal formats it is able to accept. Sometimes, what source or TV does with that info is downright maddening.
Example 1: a cable box hooked to TV via HDMI. There was a need to record some TV program to a VCR. So, ran AV cable to a VCR, began recording when needed. Turned TV off. Then, while watching the tape, got an unpleasant surprise: When TV was off, it told cavle box via HDMI that it was off, so cable box 'figured' there was no longer need to send ANY signal - including VCR. Everything from TV turn off - black screen. When TV was hooked via component, cable box would record to VCR fine - with TV on or off.
Example 2: a PC with its primary monitor connected via VGA had an HDMI going out to a receiver and from there to an HDTV. Anytime receiver was turned off, or switched to another input, PC would get an HDMI disconnect, and would completely reconfigure its desktop back to single monitor. A component connection from PC's TV out had no such problem. The only solution to get HDMI working was via a $100 Gefen HDMI detective.
Example 3: (see another thread on this very forum) Sometimes TV, detecting an HDMI connection going live will take it upon itself to switch to that HDMI - even if that is not what user wants. The usual case is again, when HDMI source is a PC with a dual-monitor setup.
With all of the above, simple setups like DVD-TV should be free of HDMI 'smartness' woes, but the signal quality should be superb and it would definitely reduce cable clutter to have a single HDMI cable back there.