I have about $300 to spend all total but was probably going to upgrade my SSD first.  My current ssd is a 120GB 840 pro system disk backed by a 1TB raid 1 (spinning rust)  My SSD and array are both about 80% full so I was looking to upgrade the SSD to a 500GB 850 evo - this lets me get the 200GB of game files off my array and to the SSD where they will benefit from the performance gain.  (before anyone says anything I have already cleaned up the old windows 10 upgrade/install files and moved my /User dir to the array)

That long drawn out explanation gets to my next upgrade my pair of GTX 260 while adequate for the games I currently play are woefully dated (and sound like jet engines as they heat up) -  
So I'm looking for a single card (would like SLI/Crossfire option down the line - normally cheaper to add another card then go full upgrade in a year or 2) that can match/exceed these for ~$150

Any recommendations would be nice (been focusing mainly on server hardware over the last year so a little out of date on desktop) - Prefer Nvidia but AMD will be considered

I'll tell you what I told the last BK who asked for advice on a new video card.

If you want to have decent frames like at least 60FPS with 1080P I suggest you wait a bit and save up at least another $100 dollars but I'd recommend $100 more to your $150. You'll get a video card with $250 that'll last you years say something like a 480, 970 or better yet 1060 4GB/1070 if you want to save $350 If you really want to play the newest titles when they come out you have to get a card with more power anything less will be wasting money. I suggest watching these videos https://www.youtube.com/watch?v=sph6cjJeRdI https://www.youtube.com/watch?v=xp6ltBCMDCE <- Language Warning.

Of course all my opinions are based on you not wanting to buy used. If you want to buy used the best you'll get for $250 would probably be a 970. For $150 USD the best you'll get used is probably a GTX 770. Which is a lot better than what you can get for $150 new which is probably just a GTX 950.

Used is fine (current were both used) - with this pair being the longest I've ever run a set of cards (as a pair 2 1/2 years and one of the cards I had for at least a year before that); normally I used to spend ~$100 every year and upgrade that way but that doesn't cut it anymore.  My monitor tops out at 1600x900 so being able to do 1080P is overkill (monitor is normally only upgraded when the old one dies; think this is my 4th one in 14 years)

In that case I'd suggest looking around local craigslist or ebay for a GTX 770 if you want to spend $150 or if you can throw in another $20 you can get a 780 non TI on ebay for $170 but I HIGHLY recommend If you plan to save up $200 and get a 970 it will most definitely last you longer.

GTX 770 $150 http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=gtx%20770&_dcat=27386&rt=nc&LH_ItemCondition=1000%7C2000%7C2500%7C3000
 
GTX 780 $170 http://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=gtx%20780&_dcat=27386&rt=nc&LH_ItemCondition=1000%7C2000%7C2500%7C3000
 
GTX 970 $200 http://www.ebay.com/sch/i.html?LH_BIN=1&_from=R40&_sacat=0&_nkw=nvidia%20gtx%20970&_dcat=27386&rt=nc&LH_ItemCondition=1000%7C2000%7C3000
 
Edit: Oh and I forgot to add; If you want to sli any of those cards, you'll need to make sure you have at least a quality brand 750 watt power supply for the 770 and 970. For the GTX 780 you'll need a 850 watt; What ever is running your old GTX 260 might not be enough if its 500 watts.