I have done a huge amount of editing in my life, but never in Windows, always on Mac. I know that you've already stated quite clearly that you're all about Windows, but iMovie is indeed sort of the standard way to go - my last film was edited in this way.
Final Cut Pro, again for Mac, is the absolute best editing program out there, used by tha' pro's, and great at creating a professional looking final product. It's a very complex program, but a lot of fun to use once you learn it. It's got all sorts of nice ways to edit and cut - slo-mo, slice cuts, text that doesn't look like a high school English project... It's got three layers of sound editing, which is fantastic for layering in ambient sound and music. What I remember most is the fantastic audio options - you can dampen sounds, add echo, distort.... all sorts of fun stuff.
I've got the mad skills when it comes to the theory/aesthetic side of editing, so I can tell you how to make it look good. I actually gave up working in film because my obsessive focus in the editing suite was too all consuming, and I don't want to be an editor. Let me boil down the two year film making course I took into the most important "rules": always cut from still to still or movement to movement, always only rotate 180 degrees or less from shot to shot, and use a reason when you do cut (person on camera's eye movement, off-frame action, audio, etc.) - never cut just for cutting's sake.
I can completely understand that you don't want to buy another system, but if you're actually looking to edit quite a bit, you could look into your local film group - for me locally, the film group charges a fairly reasonable hourly fee for using their editing suit, and they'll have suggestions for any Windows programs out there, though they will tell you what everyone is telling you; Mac is better.
I have a friend who edits at home on her PC. I can check with her and tell you which program she uses - she also prefers to use our editing suit at the office, which is a souped up version of iMovie, but since she has a new baby, working from home is a necessity to her, hence whichever program she's using on Windows. Strangely enough, she also used to live in your city, so I'll ask her how/where she edited locally. I'll be back at work in early Sept., and I'll tell you then.