I went from a Dura-Ace cassette and an Ultegra crankset, to a $28 cassette (HG-something) and and an FSA Vero crankset when I regeared my Klein. Works great! Also went from Ultegra SPD clipless pedals and Shimano shoes, back to straps and Walmart sneakers!
I only wish that my bike had downtube shifter bosses! (Then, you know what my next downgrade would be! Bye-bye DA brifters! -but I am not going to stoop to adding one of those clamp-on brackets to my Klein!)