DSLR indicates the camera design whereas HD stands for High Definition, which has many different meanings and is mostly a marketing ploy for various technologies – in the case of moderns cameras and camcorders, it’s usually referring to the ability to record High Definition video which is the higher resolution standards for video. Higher resolution means better picture quality, provided that you own an HDTV to view it.
Most of the latest generation DSLRs record HD video, so the two are not mutually exclusive features of a given camera.
I love the fact that most modern DSLR’s record in full HD. Combined with fantastic image resolution and a 1080p video function, they’re amazing for taking on the move. I actually prefer them to prosumer camcorders for filming!