Well I did my first RTW when I was 20. And yes I did have lots of fun indeed.

Nowadays I do maybe 3 to 4 RTW's a year, although I don't necessarily book them as a one ticket i.e. I am right now in Rio on my LAX-SFO-YVR-NRT-ICN-MNL-SIN-BKK-HAN-BKK-USM-BKK-SIN-CMB-SIN-BKK-AKL-SYD-SIN-LHR-BCN-ZRH-FRA-GRU-SSA-RIO-SAO-FRA-BCN-MXP-JFK-LAX trip. This is my winter break (5 weeks). Mainly on C and F, although the intra Brazil segments on JJ are in Y because that's the only thing they sell here in Brazil.

Typically I mix and match some "jumbo" fares with on going "good" premium fares and BD cash + miles redemptions F. It is not really that expensive.