Here'* how i recommend Head Units choosing to people. First set a budget, and you'll need extra over the price for either installation, or fit kits/harnesses.
Installation should be free at any good shop, major chains will do it most of the time too, a fit kit and harnesses and all will run about $20-30 as well.
First look for the technical features you'll need. All head units have pretty much the same speaker level output power. This is the 50x4 you see. If you're building a multi-amp system multiple high level pre-outs will be required, or MP3/WMA file compatability. Some headunits can be too deep, but 95% of them will fit fine.
Once you get a top 5 or 10 or whatever, use them. Find the ones that are most intuitive to you, the buttons or ***** you like. The difference between your volume being button controlled, or **** controlled can make all the difference. Some people like the lights to match the dash, some decks allow you to change the color. Do you like a face plate that moves to insert the CD or do you want an exposed cd bay? Lotsa cool things.
'06 Vee Dub GTI 2 door Tornado Red
- 2.0 Turbocharged, Intercooled, Direct Injected, 6 Speed DSG, Underbody Aero, 17" Classix
- Moonroof, Bi-Xenon headlamps, Interlagos Plaid Sport Seats, 6 Disc In-dash, iPod integration, GTI Monster Mats (winter)
'93 Bonneville SE Purple Pearl H4U package - picked up June 23, 2003, Traded-in June 28, 2007...