Well, unless you're doing lots of fancy digital effects, Premiere will do you fine without all the add-ons: I've edited a lot of shorts (DV and 16mm) on Premiere, and one DV feature, and only had to export to a more sophisticated system for the final color grading. One problem, though, is that apparently Premiere Pro removed the EDL export, which would make editing 16mm to complete on film rather pointless.
Personally, while I have Edition here (haven't installed the upgrade to Liquid Edition yet, but I doubt it's changed dramatically), I wasn't very impressed. It does seem to be much better than Premiere or Avid Xpress Pro for doing realtime effects, but otherwise I think the interface is nasty, taking over your entire desktop and violating all the basic Windows conventions.
Edition 5.0 also had some horrid user interface bugs and the DVD compression on a P4-2.4GHz was much slower than the hardware compression on my Pro-One card in Premiere. I have not at all fond memories of leaving it for two hours to produce a DVD only to discover that it had ignored the changes I made because I hadn't closed the DVD editor window. That sucked big time.
On the plus side, I never lost a project due to Edition crashing (it did crash, but the autosave meant the project was always there), unlike Premiere 6, which dies regularly and soon teaches you to hit CTRL+S every few seconds. Best of all, last time Premiere crashed and rebooted my machine it trashed my hard drive enough to lose all my captured footage as well as the project file.
So, actually, I guess I've yet to find _any_ good editing program on a PC
. Even Avid, while it has a lot of nice features, has some stupid ones too: e.g. the congenital inability to let you use the mouse for editing.