Yeah, all of those already mentioned are very nice.
Changing Pots is also a good suggestion. As well as adjusting your PU heights.
I prefer to have my Strat's Bridge PU hooked up to a Tone Control, and leave the Middle PU with a Tone Control. Even when on "10", the Tone Control seems to "load" the Bridge PU. And this seems to make it fuller, and fatter sounding. While sweetening the Highs it also seems to beef up the Mids in a nice way. And the Middle PU without a Tone Control, will have a little more "Cut" to it. Very versatile, for me.
Lowering your PUs usually goes a long ways towards a more Open sound. Of course, there will be a Vloume and Output drop. So, you will need to crank the Amp a little more. But, this is the single biggest change you can make, in my opinion. It is a huge factor in Tone, Texture/Timbre and Feel.
And then there's Neck Angle and Action. I think many don't like their Strat Bridge PU, and end up swapping out the Bridge PU for a hotter PU. And I think this is because they have to raise the Bridge PU too close to the Strings, because of the Neck Angle that is part of the construction of a Strat. If you raise your Action a little, the Strings will raise a little more, as they approach the Bridge Saddles. So, the Strings are a little higher over the area of the Bridge PU. NOW, you can raise the Bridge PU a littles and get a beefier Bridge PU Tone, and still have it far enough from the Strings, to give you a more Open sound. So, Open AND Beefy.
Just some food for thought.
As far as Pickups? Rio Grande makes some sweet stuff. Lollars, Wilde, BareKnuckles (I dif the Irish Tours!), Fender 57/62s (Especially if you can get some from the early to mid 80s. They were "improved" in the late 80s, and lost a lot IMO.), Fralins, DiMarzios, and Seymour Duncans are all great.
All of thes PUs are pretty good. The differences are usually not huge when you are talking top quality stuff. So, I recommend playing as many different Strat type guitars as possible. Ask what PUs are in each. Make some mental notes, etc.
Also, it does make a difference whether your guitar has a Maple or a Rosewood Fretboard. So, compare Apples to Apples, you know? To me, Maple Boards make the Notes "Pop" a little more. I guess it's a "quicker Attack"? While Rosewood Boards seem Fatter, Warmer and Bloom more.
Hope this helps.
Early 80's 1957 U.S. Vintage Reissue Stratocaster (Surf Green)-Warmouth Soloist Pearly Gates Neck, Pearly Gates Bridge- Larrivee D-03 (Mahogany/ Spruce)
Carmen Ghia Head- Marshall 112 Cab W/G12H 30 or Custom 4 X 6v6 Head or Budda Twinmaster Plus Head-Traynor 212 Cab w/Eminence Texas Heats.
Mo'D-Eternity-Blues Pro- Timmy-BYOC Chorus/Vibrato- TC SCF- Korg DT 10 Pedal Tuner