I went through the same dilemma just recently, starting up my video production company http://www.c5productions.com. I decided not to go HD at this time, for several reasons, not the least of which was the ongoing "format wars". I needed to get a top-quality prosumer SD camcorder.
After tons of exhaustive research, I narrowed it down to the Sony PD170 and Panasonic DVX100B. There are other great cameras in the same price range, but these two were clearly the best. It all comes down to what you intend to produce.
I decided to go with the PD170 because I will be doing a lot of event video, and its capabilities are well-suited to documentary-style and off-the-cuff shooting. If you are looking at independent film and/or studio work, I would suggest the DVX100B as it is more oriented toward well-lit and creative-styled subject matter.
Whatever you choose, it's worth it to get a great camcorder now that will last you for years. Don't be tempted to save a few hundred bucks by going with a less-capable unit. Do your research well, read lots of reviews and check out sample footage on YouTube or wherever you can find it. When you are ready to buy, http://www.bhphotovideo.com has good prices and a rock-solid reputation in the industry. Beware of "discount" internet retailers or e-Bay vendors. Most of them are scammers. Good luck!