Similar to you, i will be replacing my 51" crt rp hd set (Sony KP-51WS520) with a 52" lcd panel later this year. Recently, i did buy a Panasonic 32" lcd panel (32LX700) for the bedroom and have been comparing the two. I will disagree with a previous poster in that in my case, black levels are still better on my Sony crt rptv. When watching the Panny, dark scenes are fine but still a little washed out in comparison. Otherwise, the advantages go to the lcd for me. I enjoy watching the lcd set more. The Panny is sharper and brighter, especially on hd sources. The attributes of lcd tech really becomes evident for me when watching sporting events. Watching the NFL playoffs on this panel has been stunning! The image just "POPS" out at you, something are sets don't do. I do not get any motion blur, which seems to be the albatross of many current and past lcd sets. This Panny has a 120hz refresh rate and 6 ms. response time which i assume is eliminating any blurring. I still prefer watching the Sony for movies that have a lot of dark scenes, but i will say the more i tweak the settings on the Panny the less of an advantage it's becoming.
In summary, i have been spending too much time in the bedroom watching this panel and neglecting the old "boat anchor" in the den. So if i want to get out of the bedroom more i guess i will have to get a bigger panel for the living room!
In your case I say go for it! Just make sure you buy locally from a store with a friendly return policy. There are some nice panels coming out this year so you may want to wait a bit and do some research. Enjoy the hunt!