I am a fan of Mothers. The leather cleaner works great! The conditioner goes on and does not stay oily. I wrote a review of it in the review sticky. You can see some pics of a neglected interior and what it did for tan leather.
I have tried other that are easily available, I just found the Mothers worked the best. Meguiars always makes a reputable product, and their leather wipes are nice for a quick dusting, cleaning.
Some of the boutique stuff that I have heard good reviews on is wolfgang products. They are available on autogeek.net.
Pinup in signature by loish.net
Modded Mustangs Cobra Club#007
Military Crew E6
VOTED MM's BEST SIGNATURE 2010. THANKS STANGGTR07