I use Lexol cleaner. I buy the big jug and pour it up in a spray bottle. Works great and is easy to use. Lexol Cleaner 1 Liter From Adams Horse Supplies
For a deep conditioner, I LOVE LOVE LOVE Passier Lederbalsam. Hands down the best stuff I have used, and I have used MANY conditioners out there over the years. It's not cheap, but a little goes a long way and it really works.
Best price online, and great customer service: Browsing Store - Passier Lederbalsam Leather Conditioner
For a light weight conditioner, I really like Belvoir Step 2 Conditioner. It's a spray mix of glycerine and coconut oil. It works really well for things like bridles and saddle billets. It also is very nice for pre-show shining up. Browsing Store - Belvoir Tack Conditioner Spray 500ml
If you need an oil, for really old/stiff leather, nothing beats Hydrophane Leather Dressing. It's a light weight oil that won't darken too much and really works well. If you heat it up for a bit until it's warm, it works even better. It also helps waterproof leather, but doesn't seal it so you can clean/condition it with other products in the future. Browsing Store - Hydrophane Leather Dressing - 17oz
I've been through many, many cleaners, conditioners, and oils and these are, IMO/IME, hands down the best. I use them on English and western tack, leather halters, shoes, purses, etc.