When I first got into miniatures painting as a hobby, I did not really understand the principles of basing your minis. I would paint the whole mini up, and leave the base a little dirty, or simply paint it black.
Mind, I was eleven at the time. And since I was brand new to painting, it isn't as though my paintjobs were wonderful things being ruined by poor basing. There were a lot of basic principles that I couldn't really figure out back then.
For a while, I simply used the different kinds of flocking materials I found at hobby shops and game stores. I even tried out the green gravel that matches all of GW's basing from the 80s.
Anyway, since then I've learned how do some great basing, and how do do some good basing without a lot of work. One of my favorite tricks now is basing with cornmeal. I found out that some major painters use cornmeal for basing.
Yes, you go to the grocery store and get a cylinder of stuff that you might otherwise use to make corn bread. Glue it to the base with PVA glue or superglue, and you'll have a wonderful surface that you can paint and drybrush over.
The unpainted base tends to look like this:
Sure, the stuff is a sort of radioactive green to start out with, but after you've painted it it looks quite good:
Just a little normal base coating and drybrushing will do that. I like to apply static grass or snow over the top of cornmeal bases, and it works beautifully.
Another thing I use a lot is cork board. It gives great edges for rock surfaces. Tear a piece of cork board off of a larger piece, and glue it onto your base. Do not cut the cork board out, becuase that will give you straight edges, and the uneven look is perfect for rocks.
When painted up, cork board can look quite pleasing.
Aside from that I use normal static grass, snow flocking, water effect etc. for my basing. I found a great tutorial for applying all of these techniques for strong basing at brushtralls.com.