Hmm well if you're in Canada like your profile says then I don't have a clue what the law is, but seing as you mention direct access then I assume you're in the UK. I've been riding for nearly a year, and I've had my licence since September - all I can say is that motorbikes are brilliant! It sounds like you've never ridden a bike before, so there are 2 ways you could go about getting a licence:
1) Do a CBT (about £75), buy a cheap second-hand 125cc bike (about £400 to buy, £300 to insure) and ride it for a few months with L-plates. I had a Honda CG125, it was very friendly and great for building up my skills. Once you're happy and confident on the road you can sell the 125 for about what you payed for it; you then need to take the motorbike theory test (£20) and get a few hours training on a Direct Access bike (probably a 500cc) and then take the test. For the training and test you'll need to rent a bike from a training school, but this isn't very expensive.
2) Go in at the deep end and go on an intensive training course with the test at the end, probably lasting about a week. Again you'll need to rent a Direct Access-valid bike, and you'll have to work hard to learn all the necessary road skills in such a short space of time. This option is probably cheaper, but you'll be more likely to fail your test due to less experience.
So once you've passed your test, what's the best first bike to get? Well a lot of people buy a bike similar to the ones used for direct access tests - a 500cc parallel twin like a Honda CB500, Kawasaki ER-5 or Suzuki GS500. These bikes are easy to handle and ride, are easily capable of 100mph and are relatively comfortable over distance, as well as being relatively cheap to run and insure. If you want something a bit sportier you should look at a Suzuki SV650, Suzuki Bandit 600/650, Honda Hornet 600 or Yamaha Fazer 600. These bikes are a fair bit faster and more powerfull, but would cost more to run and insure, and the learning curve for a new rider would be a bit steeper.
Whatever you decide good luck and I'm sure you wont regret it!