A few people have recently asked me if they could play regular DVDs on a Blu-Ray player. The answer is YES. In fact, the Blue-Ray player will up-convert your DVDs to 1080i.
I think the trend will be Blue-Ray players for now on anyways. Sure, some will cost a pretty penny, but there are a few inexpensive ones out there to start. In particular, Magnavox has an entry-level Blu-Ray DVD player at a low price under $100.