Non-saxophone players look away now ...
I'm predominantly a tenor player and my weapon of choice is a P. Mauriat PMXT-66R. Its tone is a nice balance of warm and bright, it's got pretty even intonation and just feels really great under the fingers. I've customised the palm key positioning a little and I've also fashioned a bespoke F# key raiser to allow for ease of access throughout the altissimo register.
On the end of that, I put a 7* Otto Link Tone Master which gives me as much or as little bite as I need, whilst not overshadowing the character of my horn. A new mouthpiece is always the first place to look if you're after an upgrade as it's potentially a lot cheaper than a new instrument and makes a really huge difference to your sound. I've also got an ebonite link (a 7) which I occasionally pull out when I needs something a little darker.
I also think players often overlook the impact that their ligature has on the overall tone and playability of their horn, and I've used Francois Louis ligs on all my saxes for years. Regardless of what setup you use, a Francois Louis ligature just seems to give you more of whatever it was that you already liked about it! It's all about allowing the mouthpiece to resonate freely, and I even experimented with elastic hair-ties. I actually loved the sound they made (and I recommend trying it!) but they just didn't quite hold the reed in place firmly enough for me.
I use a mixture of reeds (depending on my mood!) including D'Addario Select Jazz 3S, Vandoren Java 3s (red and green box) and Legere Signature Cut 3.25s.
Having said all that, there's absolutely no amount of money you can spend that will improve your sound more than practise! Long tones, harmonics, dynamic exercises, articulation patterns and intervals are by far the cheapest way to sound your best. If you really are convinced that your horn is holding you back then go and buy something better, but beware of searching for quick fixes!
And finally ...
I also play a Buffet clarinet with a Rico mouthpiece, BG France ligature and Legere reeds, as well as a Yamaha flute and a Yamaha soprano sax with a Selmer mouthpiece, Rovner ligature and Legere reeds.