Honestly, the answer is really "no."
While it is absolutely TRUE that some TVs do a better job handling SD signals than others, and that on average, plasmas do better than LCDs, that still doesn't change the fact that SD looks crappy on any large (30" or bigger) HDTV, and the bigger the TV, the worse it looks.
SDTV resolution was determined in the 1930s(!), back when they projected that TV sets may grow to be as large as 20"! SD was never intended for the large TVs that are common today, and for the most part, TV providers are further lowering the quality of SDTV channels to allow them to carry more channels in the same space.
Also, CRTs have certain attributes that make them better at hiding the flaws in SDTV content, which shouldn't be a surprise given that CRTs were virtually the exclusive type of display for TV for 70 years.
But, despite everything I've written, you shouldn't let that stop you. HDTV isn't going anywhere, and will only become more and more common. SDTV is going away, and in a couple of years, SDTV feeds will be gone. No reason to deny yourself HDTV quality (with HD content) now, just because the SD won't look great blown up on a large TV. You'll deal with it, and before you know it, the channel will get converted to HD, even if all it shows is up-converted SD. That still looks better, upconverted from the source in much higher quality, than an SD feed.