I have an Eagle (Lowrance) Fish Elite 320- it's about 5 years old and B&W but has GPS and it's been great for me. You can find them on ebay from time to time. The new model is the FishElite 480, just more pixels but otherwise pretty much the same. They will go for under $500. If you want to save more $ you could go with the FishEasy models, same depth finder/chart but no GPS. I do love the GPS though, helps alot to mark structure, not to mention the ability to download maps. Mine came with the Lowrance MapCreate software which I do like as well.
That's my 2 cents!
Whitski