I spent 8 days there in 2009 and visited all of the WDW parks except for the water parks, IoA, Universal Studios, and Sea World. I spent a day at each park and then picked one of the non Disney parks for the extra day I had. At that pace, it felt rushed, but I was able to get in everything I wanted to do. I would have liked to spend a little more time at each to savor it a little more, but I was on a college student budget, and that's still one of the most expensive trips I've taken. Universal had a good deal last time, a pass that covers both parks and works for 7 days from the first use. As far as just entertainment, I think that was the best value in Orlando. Sea World was fairly expensive, but I was able to get a free extra day with them with the web reservation. I didn't have time to use that extra ticket though. I'm not sure how the whole Universal package works though with hotel and all since I didn't explore that option when I went.
Also, if you need transportation and are not renting a car, I highly recommend Mears shuttles. MCO is nowhere near the Orlando attractions and is a bit of a drive. I was originally looking to hire a cab, but that would have been $50-70 one way. Mears charged me $26 round trip. You share a bus with a bunch of people and make a few stops on the way out. The way back, you may get planned into that bus again, or they may just send a cab which they own. The cab with Mears is the same price and they honor the ticket you'd originally get at the airport counter. The drivers were very polite as well. Here's the link for their site:
http://www.mearstransportation.com/As far as getting around to the rest of the parks, most of the hotels offer buses to all the major attractions. If you're staying at an Orlando Resort, I doubt if they have anything going to other parks like Disney. You don't mention WDW in your plans though, so I don't think that would really be an issue for you then.