maybe an adjustable flat-wrench?
Most modern bikes don't have a single thing that an adjustable wrench would fit. For repairs on the road (which should be rare), allen wrenches and a spoke wrench are the ticket for most anything. Beyond that, you're into the specialty tools for your particular parts. For example, there are quite a few different bottom bracket tools but you only need the ones that fit yours.
Bearings these days are pretty well sealed up with rubber rings, even if they use loose ball bearings. They're not perfect, but they're probably a lot better than you're thinking. Most people who get their bikes really muddy just give them a good bath, being careful not to give bearings a high-pressure water blast that could push through the seals.
The online
Park Tool repair manual should be a lot of help to you.
As for a starter "kit," you could spend a couple hundred dollars on one of the kits sold by Performance or Nashbar for example, but most people just get the tools they need as they need them and probably end up with more of what they really need for a lower price in the long run. I do all the work on my family's bikes.
1 can someone tell me a quick way to figure out whether i have a cassette or cog set? i know on a cog set the smallest cog is a locking ring but i don't know how to recognize that.
They're the same thing. The more appropriate question might be "Do I have a cassette and freehub or do I have a freewheel?" The picture at the top of
this page should answer that adequately. Basically in the cassette & freehub system, the "clicker," ie, ratchet assembly, is part of the hub, although it can be replaced, whereas with the freewheel, it's part of the freewheel that screws onto the hub. Cassettes always slide onto the freehub body.
The problem with freewheels was that as they went to more and more speeds, the right-side hub bearings got farther and farther from the dropout in the frame, and made it easier and easier to break the axle. The freehub remedied this by putting the right-side bearings in the right end of the ratchet assembly, closer to the frame's dropout.