Hello. I've been playing for a year and now I'm searching for a new guitar. Bear in mind, I haven't dealt with any guitars so my knowledge is pretty basic.
My mind is set on Stratocaster. Problem is - I don't know the differences between couple of models: Standard SSS, Standard HSS and Blacktop HH.

Okay, I know that the Humbucker adds more gain. From what I've heard, the normal SSS is more than enough to rock, classic rock and hard rock. So, the humbucker just intensifies the "rocking" and that's it? Nothing's too totally different? The Singles are the same as the ones in SSS, right?

Last, Blacktop HH. This girl looks serious. Is this model as versatile as the standard SSS/HSS or is it more about rock and metal? Does it still suit for blues, jazz, etc..?
Who would you recommend this Blacktop model for?

Don't confuse "output" with "gain". A humbucker will give you more output and a different tone spectrum - by that I mean the humbucker in general will typically have more mids and more of a "balanced" output - the bass, mids and treble will be fairly close in output. Fender Strat single coils will typically have a "stronger" treble than anything else. DiMarzio typically has a nice chart next to their pickups which would look something like this (where I have the row of XXXX picture a bar chart):

PAF-type (vintage output) humbucker bridge pickup:

Treble: XXXXX 5
Mids: XXXXXXX 6.5
Bass: XXXXXX 6

Vintage Strat-type single coil bridge pickup:

Treble: XXXXXXXX 8
Mids: XXXXX 5
Bass: XXX 3

Of course there are all kind of custom winds for pickups that alter these readings, but this gives you an idea of the "basic" sound.

Because a humbucker has more output it will drive your amp harder - with the same settings you will find the amp is louder and will distort sooner with the humbucker. However, the type of amp you have will make a lot more difference for the type of music you want to play than the pickups in the guitar. You're not going to get a huge gain sound out of say a Princeton Reverb reissue no matter what you put into it, but a guitar with humbuckers will give you more "gain" than a single-coil guitar. A cranked-up Princeton or Deluxe will give you a "Derek and the Dominos" tone up through a Neil Young tone - assuming your neighbors don't report you to the police for running it at full volume. That's where the pedals come in; if you want a metal sound, buy a Metal Zone or some such distortion pedal and don't buy a Tube Screamer-type overdrive. Or you just have to get an amp that is designed for the music you play if you want the amp to do all the work without pedals.

It comes down to what do you want to play? If you are into modern metal a single coil is likely not going to give you the "thick" sound you are looking for even with a metal pedal (but you'll be pretty close); if you're going for classic rock (through say even some 80s metal like Malmsteen, etc.) single coils are fine.

All this isn't helping you, but hopefully this will give you some understanding of the things to look for when you go to try out the various guitars and amps. At the end of the day, let your ears be your guide. I'm kind of an "outlier" in that I've never liked the balance of an HSS guitar; I've always preferred to have a guitar with one type of pickups on it (all single coils, all humbuckers, or all soapbars) and get my "boost" from either a pedal or my amp. However, many people like to have that "boost" that comes from being able to go from the "quieter" single coil tone for chord work to the "louder" bridge humbucker for leads by just flicking the selector switch.

Personally I'd suggest a HSS model. Even though I don't own one I don't like the bridge tone in the SSS models and figure a humbucker might be a nice change.

The Black Top models might be Fender trying to offer Gibson type tones but I've never played one so I'm just talking out of my butt.

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