Of course these are overdone, but I am afraid I can't look to anyone else for advice.

I need a new guitar to suit my new style - light rock, blues, and jazz.

I was thinking
do I get an American Stratocaster?
do I get a Standard Strat, and add my own things?

I realize, if I do get the American strat, I won't have construction problems and such... and it comes with a case, and everything....

I thought I wanted a different set of pickups - I wanted the Fender Hot Rod pups (I dunno - thats the name I remember)... and I wanted to add Schaller locking tuners, and LSR roller nut. (Of course, If I tried to add these things onto the American, I wouldn't have enough money...)

In summary:
An American Stratocaster


A Standard MIM Stratocaster with the following upgrades
Schaller Locking tuners
LSR Roller nut
Fender Hot pups
and Fender American tremolo system.

The thing is - the second option is only about a 100 dollars less than just getting the american.

I dunno. advice on these things please. Persuade me from buying or not buying the upgrades - are they really helpful, is the american tremolo any better than "synchronized" ones that come standard on the Mexican strats...? etc...
For what you want, including the jazz, get yourself either a used MIA G&L Legacy or a new Tribute G&L. The PTB (passive treble/bass) system will come in very handy for jazz tones, they are MUCH better build quality than the corresponding Fenders, and have infinitely more of Leo's heart in them.
Id go with the G&L, or maybe a good ES-335-style guitar. very different tones than the single-coils, but still get some nice jazz sounds and great blues sounds from it.