Tamiya T55, was susposed to be the best engineered kit ever!
Some of the new DML 3´n1 251s or tiger. The great thing about these kits, is that all you need is in the box. PE, indy tracks, metal barrels etc. Check out the reviews to see whats included.
Or how about some dragon or tamiya 1/16 figures if the previous are too expensive. These are great quick projects where you need to learn how to paint a figure properly. This skills will improve you 1/35 figures 100% afterwards.
Just my 2 euro cents!