The short answer is... yes! IMO you should have unique meta descriptions on every page of your site specifically worded to convince people to click on your link on SERPs and describing what that particular page is about. I'm just curious, do your pages currently rank? If so, I'm curious what description is being displayed beneath your title on the SERPs? My guess is since you probably don't have a DMOZ entry and admittedly don't have a meta description, so the SEs must be pulling random text from your content on the page. I would want to control what shows up in the description on the SERPs for those pages, not have Google randomly picking text from my page to display.
Create a meta description unique to each page with a call to action - "Choose from the best selection of Sony TVs. We have non-HD and HDTV, LCD and Plasma... blah blah blah." Include your 1-4 keyword phrases that your page is supposed to rank for.
[edited by: ZydoSEO at 6:03 pm (utc) on Dec. 17, 2007]