I know this is redundant and despire the fact that Toshiba's HD DVD, marketed primarilly for low price points on the players, has been supplanted by Blu-Ray (HD DVD also used a blue ray laser of a different type).
If you have a display of 42" and smaller and your are viewing it from 8 to 12 feet, you won't appreciate the blu-ray picture over an upscaler 420p standard DVD player -- I have a SONY that does upscale even t0 1080p if you use an HDMI connection. 1080p capable Blu-Ray players are still too pricey and the discs still too expensive. Dish Satellite is now broadcasting VOD in 1080p but it's going to be years before we see it as a standard, being it's lucky if you get 1080i (mis-identified as 720p as the "p" stands for progressive and all 1080i is interlaced). Progressive means the picture is scanned with the pixels in line across the screen progressively. Standard DVD's are 420p are upscaled beautifully to 1080p. However, on the screen size mentioned, you won't see any difference unless you are right on top of the screen.
I'd buy a good DVD player with upscaled but bare in mind that you do have to have an HDMI input to appreciate the improvement on screens 46" clear up to 100" (where 1080p is, of course, a remarkable difference even when too close to the screen). Sitting that close to any big screen is tantamount to sitting in the first few rows at a movie theater, so if that's your bag.
BTW, Pioneer has dropped their entire line of Plasmas, leaving only Panasonic producing the lion's share of those sets. Plasma is likely to phase out in lieu of new technology even beyond LCD. They use way too much power to boot!