Cartridge for my system? Your wisdom is needed

Analog Gurus

The time has come that I am making another change in my front end analog system and I this is going to be my final one for a long while.
I know it sounds familiar but its true, other things are taking precedence over my hobby and I need that to happen 
I am looking for a phono cartridge for my front end analog rig, price is a factor so nothing over $850 since I know there is plenty out there up to this range.

My preference is, neutrality and ultra-resolution with lots of gain
The analog combo is not based of the norm and I am going to make them work together to the best possible manner

Expected synergy for my combination:

Brinkmann Bardo
Tonearm – SME 4.5 custom board from Brinkmann
Phono Preamp – Graham Slee Era Gold with Elevator (so the cartridge can be either MM or MC)

I need a cartridge that will compliment this system, Ayre amplification with a pair of Wilson Sophia’s II
I would like to try a good MC for this but will gladly settle for an excellent MM as well

Ortofon 2M Black is on the list so far and looking for more suggestions and wisdom from all of you out there.
Thanks - R
Dear Rapogee: All posted advices are very good especially the Maestro one.

Inside your budget INHO this latest AT model is a very good alternative too:

Regards and enjoy the music,
I'd agree with Tom_hankins that Grados in the stated price range are not ultra resolution champs. They are not my idea of neutral either, although they sure sound pretty.
I have Ortofon SL15 e MKii running with Ortofon MCA76 phono amp. It sounds pretty good, beating my friend's Denon 103R. I also have MC20 and MC100, all of them quite as good as SL15 e MKii. Each of these old Ortofon catridges in NOS or in very good condition can be purchase at under $200 from eBay, and MCA76 or T20 SUT at under $300. These comb at a little bit over $400 would easily beat most cartridges at under $1000.
One catch is that you may get a lemon. You can't be 100% sure for 40~50 year old products.
If you want ultra-resolution, Dynavector 17d3 is hard to beat but its price is a little out of your range. The discontinued 17d2 MkII will be in your price range. It is just as good but you should look for unopened NOS box. I will recommend against buying used cart unless you know the owner personally and how he/she handles the cart.