I used Premiere Pro 1.5 and Liquid Edition Pro 6.1 on the windows platform before switching to Mac, since I couldn't afford to get FCP, I bought FCE to hold me over (mostly, I edit graduation videos, slideshows, will be doing some video podcast work soon for where I work, and other misc. stuff) and to be honest, it has worked really wonderfully. For what I normally use it for (cutting video, adding audio, transitions, titles, slide shows, green screen) it's actually more then enough.
There are some things in FCP I wish were in FCE or available separately (DVD Studio, compressor); but I've used DV footage from a sony handycam and HD footage from a canon HF100 and FCE has worked wonderfully so far, and honestly I think you'll find it incredibly powerful (and possibly a bit intimidating if you've never worked with timeline based editing before). For home use, it's got a lot of features, and you can get some wonderful plugins for it if you want to extend its already incredible capabilities. There are quite a few free plugins (if you plan on doing slideshows with the burns effect (the basic method that stills are done in iMovie 08 (possibly other versions too, I just have 08)) you'll want to get a plugin to make it easier otherwise there is a bunch of manual stuff you will need to do. (check out:
Auto Pan Zoom ) which is a free and very useful plugin to automate the process if you want the ken burns effect.
to kind of give you a feel for FCE - take a look at this video course on using it:
Izzy Video » Learn Final Cut Express 4 | Learn how to shoot, edit, and produce better video.
it's a free download, and although it's meant to work with you stepping you through doing the things on the program, you can get a feel for it watching the videos.
The only real negative is DVD production - if you're just going for home use, iDVD is great - if you want a bit more control and possibly to distribute copies of, IMHO iDVD isn't so great. DVD Studio Pro looks awesome, but is only available with Final Cut Studio (an older version can be found on ebay but...) I ended up compromising until I could afford FCS and bought moviegate which gives me just enough added control over the DVD creation to make me happy. It's one of the few things I haven't found my "ideal" solution for.