I've been shooting for over 3 decades now, just a baby compared to others. Here is my suggestion.
Get the basics down first. You seem to have done that. Then borrow or rent different guns and try them. See what you like.
Even now sometimes I'll aproach a shooter at a range I'm at and tell him I'm thinking of buying what ever he's shooting. Then ask him his opinion of it, any suggestions he might have for me, then after all the small talk I'll ask if I can try a cylinder full, or a magazine full. I have only had one shooter turn me down. He had fired his last ammo just before I started talking to him.
Once you have tried a few, you'll be in a better posession to know what you want.
Some of the guns / rounds I have fired by my small talk method:
Flintlock rifle in an indoor range, (choke gag haka haka, fun tho)
Winchester 70 in .458 Win Mag. ( This put the grimace in ouch)
S&W Mdl. 57 .41 Mag.
M1 Garand
Colt SAA in 32-20
M-60
M-16
Reising SMG
Various .45 Autos
Browing Hi Power (Load on Sunday and shoot all week applies)
Glock 9 mm (Boring)
Broomhandle Mauser in the little bottle necked round.
S&W 29 4"
S&W 6" L Frame .357
NM Super Blackhawk .44 Mag. (I hate that dragoon grip frame)
SS Ruger Vaquro in .44 Mag with Hogue rubber grips (OUCH)
BIG bore muzzel loading rifle. (Owner said it recoiled like a 12 guage- RIGHTTTTT a 3" mag 12 guage.)
A funny cartrige cap fired single shot bp rifle.
I'm sorry I got carried away. I reminded myself how many guns I have got to fire just by talking to other shooters.
I think I'm going to the range tomorrow. Never know, I might get to add something to my list.