+1 to SV. SmFizz, its like asking if u work at Davis. If ppl find a good thing, best to share it with others. I for one do the exact same thing as Ryan. There's nothing wrong is there? In any case, SV does have very good stuff on offer, anyone who's tried their Timbre, Swing and Marlique ranges of guitars will attest to that.
Alright, back to the topic.
1. 3 main types: Hollow ( Gibson/Epiphone ES335 ), semi-hollow ( Ibanez PGMs i think ) and solid ( Fender Tele/Strat, and most others ). Amps there are 3 types: solid-state, tube or valve and hybrid amps ( combination of tube and SS, a rather confusing notion i know ). Best to Google or Wiki.
2. Differences are mainly in the tone, hollow and semi-hollows tend to sound more..........well, hollow, due to there being air spaces behind the pickups Solid bodies sound more................lolz, solid, due to the fact there that is no air space for the sound to resonate. BUT, pickups, amp, pedals, EQ, blah blah blah also count a lot towards tone, so don't be too worried abt this yet. Best to start with a solid-body. Safest option IMHO.
3. Many shops around, most mentioned above, shld be enough to keep u busy hunting around for a while. Best to go with someone who has experience, as a few places might try to fleece u.
For your first guitar, i recommend u go and do proper research b4 taking the plunge, it wld be a lose-lose situation if ur first guitar is something u dun like. Maybe u cld post wat bands u listen to, songs u like, wat kinda sound u looking for ( eg. thick and warm ) so we can recommend u stuff. Cheerz!