This list assumes, of course, that you already have a computer. You don't need the fastest computer to record and mix music, but it should be reasonably fast. Anything with a Core i- or even Core 2-series processor should do the trick. Just don't use a netbook.
Ashford & Simpson also had success writing for themselves: Perhaps the best-known song they sang was the 1980s hit Solid As A Rock.. His music is unmatched in terms of great songwriting, Verdine White of Earth, Wind and Fire said after learning of his friend's death.
It wasn't until he decided to try a vocal that he finally hit #1 on the Billboard charts with This Guy's in Love With You in 1968. After the breakup of the Tijuana Brass, Alpert was out of the public eye until his comeback album, Rise, hit the charts in 1979. That album produced his first instrumental #1, Rise.