MBothe, first is first, I'm new to diving as well, havent even done my certification dive yet (3 weeks away)...
you wont get much say in where you dive. unless you do the shark dive, or the dolphin dive.. the operators will decide where you dive. if you spend a week there and keep going with the same operators.. maybe they might swing something for you.. but as my friends here on the board and in the real world have told me,.. the operators chose the daily dive sites based on conditions.. this is true pretty much anywhere.. but if youre nice theyd probably consider requests.. mind you if you want to go to the top rated sites.. theyve probably seen them far too many times and they know that those sites are trashed as well.
but i know what you're asking for and the answer is, in no particular order: shark dive, dolphin dive, mary's place, prince albert wreck, valley of the kings,... these are among the most talked about dives on roatan.. but again.. if you want to get on a boat knowing youre for sure going to a certain site.. youll only get that with the shark dive and the dolphin dive.
the dolphin dive sounds like one of those hit or miss things where if the dolphins dont want to play that day.. well.. youre sitting around looking at a muck bottom. the shark dive, or anything for that matter on the south side, are more advanced dives and if you dont have 30 or more dives under your weight belt, well, you may want to consider the reef on the north side.
and i have to say it, but if youre thinking about the shark dive.. you may want to check out another thread on this forum regarding that matter.