+1 Griots Garage Leather Care (Spray). This stuff is good 2-in-1 cleaner and conditioner that I like to use as part of my weekly wash routine, applied with a microfiber cloth. For a more thorough detailing, I use Griots Interior Cleaner Spray (applied with microfiber cloth) and follow up with Griots Leather Rejuvenator (applied with foam applicator pad/sponge). Check "where to buy" on the Griots homepage -- they are starting to sell products at auto parts stores, so you can save the time and cost of shipping. The Griots products have a nice natural leather smell (except Interior Cleaner which has no smell really).
I've experimented with the Leatherique products: Leatherique Rejuvinator Oil followed by Leatherique Prestine Clean (process sounds backwards, I know). Great results, but a lot of time and elbow grease is involved.
No matter what you go with, be careful not to over-saturate trim panels (doors, dash, etc.) -- you risk weakening the glue and having the leather bubble up around creases, curves and indents.
Above all, keep the ArmorAll away from your leather!