As the man says above. Alpine are very very good for HU's Even there cheap stuff is top notch!
Pioneer are having some bad problems latly with earth tracks, i believe this is fixed in their late 08 models though!
The alpine x100 is very good if you have an ipod you will use all the time!
I have an ipod connection onto my existing HU soi can ride normally on CD's then when my mates get in, they plug in their ipods and away we go.
Costs ~ £50 for the full speed connection though! Aldo the alpine unit has to support ai-net.
You could however just use an ai-net to 3.5mm jack (doesnt charge your ipod, neither does it control it from you HU but it still plays ok (quieter though) for ~10 of the bay from china :clown: