Well, if you can purchase locally, you'll save a LOT of money on shipping. When I was researching these last fall, I found some "great" prices on sets only to discover that shipping was more costly than the set itself.
If you have the time/patience, Craigslist is a wonderful place to find exercise equipment. There are lots of discouraged ex-exercisers sometimes even giving things away!
That being said, I LOVE my weight set. :)
You can purchase a set of resistance bands, which are a lot more portable, versatile, and inexpensive than a weight set.
I only know 1 person with the adjustable block weights and she hates them.
If you are set on having chunks of metal in your house, I suggest 2 kettlebells, 8kg, 12kg.
Reebok makes a realy cool set that locks the weights in and out, so if you're switching from 10 pounds to 15 pounds, say, then you just put the bar in and lock your extra weights on. It looks very cool but it's expensive. I think Target sells them. Bowflex makes a set like that also. A good buy is a set that comes with free weights and a bar, like a mini barbell and you switch them on and off as you need to change them up, but htey're
Thanks for all of the feedback!