If it is in relatively good shape, I would go for it. Think of it this way, would you pay $17000 for a used '01 GC Limited if you knew exactly how it was maintained and driven? You probably would right?
Besides the transmissions fluid change, you should also consider changing the fluid in the transfer case and axles. For the record, I use Mobil 1 in everything: engine, transmission, transfer case, and axles. I wouldn't suggest paying $50 for a transmission service. It is a very easy job as is the t-case and axles. I do a complete change every 24K on both of mine. If you have any questions on the job, shoot me a PM. I'll be happy to help you out.
As far as the shocks go, you are probably looking at a replacement at around 75k or so. Shocks are a funny deal. They seem normal to you until you change them. You actually get used to them as they gradually wear out. Even at 50k you would notice a difference if you were to change them now.
On the 4.0L L6 or the 4.7L V8, a good safe time to tune the thing up is around 60k. Just for the sake of routine maintanance, flush and fill the radiator, and replace the accessory drive belt. It should be ready to go.
01 Cherokee Sport 4x4, 4.0, Auto