If you're really nitpicky about the type of tape I use...
Type 1 Normal Bias Low Noise
High-flux density oxide formula (whatever that means)
30 minutes to a side
The Radio Shack brand
I have no idea what I'm talking about.  I just buy the cheapest tapes.  (I'm paying with my lunch money here)  The other day I made a tape for one of my friends, and I was surprised that the quality wasn't really bad or anything.  I mean, it wasn't noticeably crappy.  And it was only $2 for two tapes.  So I'll just stick to using these tapes until I have a really good reason to use a different kind.