$800 to spend on speakers, $1500 on whole system

I recently bought an integrated amp that I'm really impressed with for the money, and at a pretty good discount.  For you I'd suggest the Nad C356DAC, normally it goes for about 900, but is on sale at this time of year as they clear out the factory refreshed stuff.  

You should be able to get it for about $650 at spearitsound(click on the "used, demos and specials" link on the home page), if you are decided on getting a DAC, which is a module installed in this Nad.  Speakers, for 800 or less, you might be better off with a bookshelf as towers at this price range are pretty entry level.  

A great option for bookshelf speakers is an internet direct dealer like Ascend Acoustics.  The Sierra-1 outperforms anything at the same price range of $750 because they don't have the usual mark up of  the wholesale/retail brands.  

A couple of really good options to chew on!

So you've got 600 or less for speakers, after spending 900 for the integrated amp.  Perhaps those encouraging this purchase could advise.  I expect they'll advise you to up your budget.  

The chances that a dealer is going to let someone demo speakers at home is pretty slim these days, let's try to be realistic here.  

The difference in sound qualities of an 1800 system and a 1500 one is probably not worth the 300 though.