The John Grimes
series by Bertram Chandler
. Space Opera at its best. Follow John all the way from Lieutenant to Commodore to Rim Runner. Bubble helmets and bikini-clad space vixens.
This is fun. I've been collecting the original First Editions where i can.
The Deathworld Trilogy by Harry Harrison.
Forgot about these-really worth a read. Fascinating concept and excellent resolution. Lots of fun.