I like jogging/biking down the main highway (Autovia de Poniente) towards the sea at Santa Ponsa, Mallorca just at sunset. The silhouette of the town against the sea is just perfect - a quintessential Spanish skyline:
http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=santa+ponsa+mallorca&sll=37.0625,-95.677068&sspn=51.222969,114.257812&ie=UTF8&ll=39.51702,2.502179&spn=0.024598,0.05579&t=h&z=15

If you're around that area don't forget to bring some cat food for the wild population to pay your toll.

Palma is very picturesque too, there's the cathedral and quite a few nice locales.. but then again it's hit heavy by the 'Ikea-ization' of Europe and it'd be a bit harder to get good stocks shot due to the modernization creeping in everywhere.  I really like the tip of the island by Santa Ponsa because it's just seems like the place where the sun sets is the greatest vibe - there are outdoor DJs and concerts nearly every night for a lot of the year and there's always music in the air till late in the morning.  The Mallorcans remind me a lot of Hawaiians or other Polynesian peoples - just very laid back.  The south-west (by Santa Ponsa) and north-east are probably the most picturesque landscape-wise - big cliffs, nice beaches. 

I think it would be a shame if you stuck around only in Palma, there is so much to see (and shoot) and hey, it's Spain, if you are only keeping up with traffic you are already driving like a madman.