definitely go with a 22LR to learn, but i find that most NEW shooters prefer a semi over a revolver. the grip is just more intuitive and comfortable for MOST people who haven't been handling revolvers for years. yes it is slightly more complicated to operate, but if some drugged out gangbangers can figure it out, so can you. to slightly simplify the semi, i do recommend going for a striker fire if you are going to be using it for self defense. this way you have the point and pull simplicity that a revolver offers in a more comfortable weapon with a higher round count. there is a reason that no law enforcement or military currently use revolvers. my opinion is that they are an inferior platform for the purpose of self defense.
as to models to try, this will depend upon personal taste and genetics. obviously you need to be comfortable with it, but it also needs to fit your hand. some semis have larger grip frames than others. depending upon your hand size, this can make it difficult to comfortably hold the gun and reach the trigger. this is especially true of striker fire. my list below are models i recommend. i will put a * by options with narrower grip frames and a # by options that easily conceal. at the end i will put an S by striker fire models. i will limit the choices to models that i believe will be good for self defense.
sig p226
sig p229 #
sig sp2022 *
walther ppq * S
walther pps # * S
cz 75b
cz 75d compact (pcr) #
S&W M&P * S
S&W M&P compact # * S
Ruger SR9 * S
Ruger SR9c # * S
