Some excellent advice there, certainly a bridge camera will give you a lot more control than your current one and I reckon based on what you have told us it is the right choice.
I have a Canon 40D which I love to bits but some time it is just too much to lug around so I invested in a Canon SX10IS and am really impressed with it.
Before you go for an SX120 which you seem to favor there are a couple of things to consider that the SX20 has, firstly it has double the optical Zoom range and secondly a flip out display, these are really handy firstly you can angle it to get more awkward shots and secondly you can fold the screen away so it is unexposed so won't get scratched etc, also there is the shutter response time to consider which I believe will be quicker on the SX20. COmes back to finding a Camera shop that wants your business and will let you try the cameras.
Tripods were mentioned earlier, I agree they are quite chunky to lug around, however you may want to think about something like a Gorilla pod which is more portable and can be wrapped around fences etc to give stability, they are compact as well, I would only consider this if you are going to get into situations where you think you will need one.
Finally consider joining a camera club, they can give specific advice and of course provide inspiration, I have also got a lot of great advice from books, magazines and forums such as this. Also they may be able to recomend specific courses., if you do want to go down the course route then look carefully as the Digital Photography ones seem to be from my experience more about using the basic functions of the camera, getting your pictures off and basic manipulation.
Enjoy
