ok...now that aalbert has broken the ice I'll confess...
The strobist stuff is the way to go...
www.strobist.blogspot.com
I purchased the a Smith Victor 4 light hotlight setup (approx $425 street price) used on eBay for $175.... Used it a couple times, and realized the limitations... End result, is that kit sits unused.
Next step was to buy a used Broncolor 3 flash setup.... This is a 15-20yr old kit, from a Swiss company, who makes some of the best stuff around today (this was their econo line at the time). Once I used that, I realized how nice it was to have pure light, to be able to use 1/3 power in one spot vs. another, how cool snooting something could be, etc..... I like this set, and have since purchased another head (4 light setup), and an additional 5' tall softbox..... Is really cool, but if you look, the case is also really big, and setup time is longer than expected.

Then for work, I needed to shoot some interiors .... Hmm... having to setup A/C powered flashes became problematic, due to time, power availability, and space.... Enter in the strobist approach. You get standard on-camera flashes, and you move them off camera. So I purchased some used Manfrotto light stands off eBay ($20-30 each), some Lastolite umbrellas ($20 each), a hotshoe/umbrellas adapter for my stands ($25 each - go with metal ones), and a set of radio triggers ($20-200 each).... So in my bag I carry 4 flashes now, that I can setup in stands, or by themselves (they hide nicely) - I also have a lacrosse bag that I keep in my car with the stands / umbrellas, so even if I didn't plan on shooting strobist, I have the equipment when I need it (will already have my bag with flashes along). Given the size of the equipment, I also have several Lumiquest light modifiers, that ride in the side pocket of my bag (along with the triggers), so sometimes I can even just lay them on the ground/shelves/ etc. and go to town. When I want to setup a simple umbrella or two, it takes 3-5 minutes from start to finish - which means you are more likely to do it, than skip it.

Shots below aren't quite portfolio material, but had the equipment not been accessible, and easy to use, the shots would not have happened.
Impromptu shot of my son a couple days ago after getting home from school. Using sun as backlight, off camera 580 in Manual mode with Stoffen - "strobist style".

Impromptu umbrella shot, of local musician Bryan Laye, shot Friday night... Because the equipment is light and easy to set up, I had it with me, and used it.

So look on the Strobist link that rpavich shared, and also check out their Flickr pool... With a combination of flashes / triggers / umbrellas to start with, you can do a lot.... and price wise, there is a lot of latitude, so there is usually something for all budgets.