It's not enough to just have good Software. If you want to do more than just basic editing then you need to have the gear to back up the software and help complete the editing tasks that you are asking the software to do.
An upgraded video/graphics card, processor, memory, power, all come into play when you start doing a little more than basic stuff.
A lot of software packages will get the job done but they could be a lot better with the right equipment and the more expensive stuff offers a ton of more features.
I'm currently using Premier Pro CS3 and filming/editing everything in HDV. Using a Matrox RTX2 realtime editing engine, with Diamond Radeon HD3870 512mb video card.
I do my editing as work, but it gets to be just as addicting and fun as a hobby and you'll start to discover what works and what doesn't just like everything else and your needs will start to grow very quickly.