I'm looking to buy a new DSLR but have absolutely no clue as to where to begin looking!!

I'm looking for something that is really good for zooming and the differences in light (day to dusk to dark). A friend mentioned that to get good picture quality it's more to do with the lens rather than what megapixel the camera holds...is this true? If so, what is a decent lense spec etc because I have numbers being thrown at me left right and centre when it comes to searching for cameras!

I'm willing to spend hours and hours and hours on getting used to the camera and playing around with the settings to get the "perfect picture" - my little project with the max price being 500 (all I've saved being a student!) However, I have noticed that some of the 600-700 price range go for 500ish on ebay and theyre from companies rather some dodgy individual etc and they seem to come in good packages (with 2-3 years warranty) eg: including tripod, extra lense, memory card etc - are these any good or am I better off buying direct say from nikon or canon or high street shop etc?

please help because I haven't a clue what to look for and I'm absolutely dying to buy one!

Thank you!