use ebay only as a reference. its usually much cheaper in the market than ebay. however, if its second hand then ebay is ok.
i dont think u require anything above 3MP for ur needs. also its not just the MP but the quality of the lens also that produces good images. so go for a good company like sony or nikon (they use carl zeiss and nikor lenses respectively, and excellent clarity). though u may get higher MP from cheaper companies.
also some companies, have only a 2MP sensor but claim 5 or even 6MP via interpolation. avoid these like the plague. they might be very cheap, around 5k for a 5MP camera. DONT FALL FOR IT.
optical zoom is very important and should be considered as important as the lens, resolution. DO NOT EVEN BOTHER ABOUT DIGITAL ZOOM.
stick with a sony or nikon and u should be fine. i prefer a sony as i find its image quality slightly better and ofcorse the better night shots as it has a great flash.
raghunandan.