I'm a huge RCCL fan, here is a rundown of the newer ships
Voyager Class ships which are the biggest ships in their fleet with the climbing wall, ice rink, promenade etc.
Here they are from oldest to newest:
Voyager of the Seas was first in late 1999 (I sailed her in 1/00)
Exporer of the Seas was next in 2000
Adventure of the Seas
Navigator of the Seas
Mariner of the Seas in 2003
Then there are the Radiance class of ships, they are slightly larger than
DCL ships. They have rock climbing, mini golf, but do not have the promenade or the ice rink. (They are very beautiful ships though, with tons of glass everywhere to see outside while you are on the interior of the ship). Great ships for alaska IMHO.
Radiance of the Seas is the first sailed around 2001 I beleive
Brialliance of the Seas
Serenade of the Seas
Jewel of the Seas
I'm not sure of the original sail dates of these, but I believe both the Serenade and the Jewel came out this year.
Hope this helps!