So, a fellow Aerial owner!
Actually, I feel three identical LCR speakers are the best possible choice. However, three LR5's or two LR5's and a CC5 will probably be 5k minimum.
A less expensive option, though more difficult to find, would be two LR3's and a CC3B: or, three LR3's.
Current Equipment: Datasat LS10 w/ Atmos and DIRAC. Datasat RA7300, Aerial Acoustics LR5's (LCR), Aerial Acoustics LR3's (sides), RBH in-walls (rears), Seaton Submersive, Marantz VP15s1, 106" Carada BW screen, Oppo BDP-103.