Best distance from your beloved speakers?

Quad 63s / gradient63 sub....4.5 feet speaker to ears.
Speakers 7.5 feet center to center apart.
Nearfield is sweet.
about 12 feet back
You don't mention room size - so I'm just guessing - I'd sit about 8.5 ft (from speaker to ear). Thats the ratio I used for my Quads, but it really depends alot on the acoustics of your room.
I think you are sitting way too close to the speakers. If your speakers are 7.5 feet apart, the minimum distance you sit from the speakers should be the same or preferably further. The #1 key with Quad's is positioning. You need a lot of room behind them, the more the better to reduce interference of the back wall and bass frequency being cancelled out from reflection at the back. The sides are not as important but the back space will determine how they sound. Mine are good 10 feet from the back wall. As a rule of thumb, the Quad's should be sitting roughly 1/3 of the length of your room. You need a long narrow room for Quad's. I find Quad's have wondefful bass if you have the room behind them and the right amp for them. I never felt I need a subwoofer. The room and the space behind your Quad's and the right amp dictate how much bass you hear. If you don't have the room behind your Quad's, they will sound bright and forward. The reflection from the back wall and the cancelling of bass frequency will let you not hear the full frequencies (lack of bass) and that's why it sound bright, glare and forward.
Okay, I am now 6 feet from speakers....still excellent articulation and focus. My room is exactly what you sugest. 35 feet by 16 feet or so. Speakers 12 feet from front wall. The depth of the sound stage....reaches from listner right back to front wall. Amazing.