We got a very good low-end programmable DVD player for about $60 last December. It works fine with my 25-year-old TV and movie DVDs only cost about $10-20. I still use my VHS for my older movies and older Cathe tapes (I run them through my stereo system, which has three video inputs, but if you don't have a stereo, you can hook a DVD player into your VCR's video input jacks in the back.) Seriously, it has been worth it, mostly for the workout benefits. The only workout DVD I have right now is Pure Strength, but having it on DVD has given me a lot of flexibility. I've preordered the Body Blast along with one of the Intensity DVDs... I've been saving up since January "just in case."
Also, I expect DVD prices to drop in the future as the technology develops.
An added benefit to DVDs? My 7-year-old decided to watch "Ice Age" in Spanish today... and next he wants to watch it in French. You couldn't do that with a VHS.