To keep really beautiful leather looking good, take the natural oil from your face and rub it on the leather. (Yuk- but it is what the old craftsmen do!)
I like Lexol and/or most saddle soaps and conditioners -- I have had 3 of my own horses and plenty of expensive leather saddlery (tack) as a result!!
You may be able to find Lexol in a super-store (ie: Wal*Mart), but if not, any Tack Shop and many pet stores (PetSmart has an entire equine section in it) should carry this or something similar. Also, Murphy's Oil Soap works well in a pinch!! Currently I use Horseman's 1-step Leather cleaner & conditioner (comes in a small tub). For suede, please check instructions as there are special "suede washes" normally.
Be sure to use a soft, soft sponge (or tack sponge--small, cylinder-shaped, fits in palm of hand) or a SOFT cloth to apply.