Howard, If you are about to purchase some products, why not ask GIK to draw up a treatment plan for your room? I believe whatever fee they charge will be credited against your first purchase.
Even if you don't buy everything they recommend, a plan will give you some ideas.
My big three in treating a room are:
1. Enough absorption/diffusion to eliminate slap echo everywhere
2. Absorption at 1st reflection points, at least on sidewalls and maybe also ceiling
3. Bass traps in corners to reduce boom and hangover
I like to use products (like GIK Alpha panels) that will provide absorption and diffusion. If you use a lot of pure absorption, it can deaden the room too much, as you noted.
Yes, bass traps typically will reduce echo.
Hope that helps!