Best Speakers for 2channel Music

Riley804 is exactly correct. Great advice. So much depends on room size and room content. But assuming the room is moderate in size, you have many many choices. If you're wanting to purchase only brand new speakers, recommendations include NHT, PSB, B&W, KEF, ProAc, Energy, Epos, etc. To find a decent full range 2-1/2 or 3 way speaker brand new for $800.00 might be a stretch. Perhaps a very good standmount with decent bass ext is the way to go. It all depends on if you want to buy new or preowned. All the best in your search.

Magnepan MG12's or stretch the budget for MG1.6's.

Currently I have a harman kardon hk3480 reciever and a 12 inch sub. Not too much high tech or expensive stuff.

Magnepans require too much power for you Harmon Kardon, and the placement of them requires alot of room from back wall. They are great speakers but too many suggest them before they really know if they are ideal.