DLSRs force you to record separate audio to get decent results. They are still cameras with video capabilities at the end of the day. They take great pictures, but are a bit cumbersome (interface wise) to use on set... although the increased image happy may outweigh that for you as it has for many folks - I'm even starting to lean that way a bit.
Sorry, knightly, I agree with so much of what you say on these boards. Not this time around. DSLR doesn't force you to record seperate audio (though, it's definitely a damn good idea). Plugging an XLR into any HDV camera will get you
slightly better audio results than plugging an unbalanced mic into a DSLR. But at the end of the day, I really think you need a quality preamp, and as far as I know (correct me if I'm wrong, anybody), you're not going to get that on any HDV camera. So, either way, if you want quality audio, you need an external recorder.
Cumbersome? No way. I've been using the T2i extensively for the last month. I've found it no less easy to work with than Canon GL1 and Sony VX2100 cameras that I first learned how to make movies with.
On a sidenote, knightly, I don't recommend the T2i, or any other DSLR for documentary-making, just in case that's what you were considering it for. As a second camera, it'd be pretty sweet. Narrowing the depth of field can be a really useful tool for talking-heads-style interview footage. But for having a camera that needs to be out and about, on the go, this ain't the one. Overheating is an issue, and auto-focus is a non-feature. For narrative filmmaking, auto-focus is stupid; but on a documentary-shoot, it's convenience can be a life-saver.