Depends on what you are looking for. I went from the toyota factory nav to the 6610. The price for the 6610 and the factory nav from oemvalue.com is almost the same, but with the 6610 you get a whole lot more function. So that was my choice. There are other models out there that are less expensive but have less features. So do some research and find the best one that fits your needs. Good Luck!
I paid $969 for my avn5500 w/ipc-106 ipod adaptor shipped to the house from cartronixplus. I don't believe that you'll go wrong with any eclipse unit either but if you cherrish full ipod control get an 07 model. The 06's have limited ipod control and it is the biggest drawback to getting one.