this is a cool download to help you write down solos and stuff. it’s very easy to use, is inexpensive and has a good demo feature.

makers of amadeus software, a very easy to use simple program for converting files to different formats edit and basic dsp. i use this almost every day. it's really a cool easy to use program.

makers of max/msp and many other useful creative pieces of software. definately worth looking into, if you like that sort of thing. they have a great site.

stefan makes some really cool software.
if you are interested in audio manipulation, check out his kenaxis program.
it's very hip.