best possible indoor antenna

Might not be quite in the same league with some of the more expensive antennea, but Rat Shack has an FM-only 70" outdoor antenna ($23!!)that may fit nicely in your attic. Because it's not that big, it's not that directional. (Generally, the larger a boom antenna is, the more directional it is.) DO NOT get a combo TV-FM antenna if you want to maximize performance as the TV portion can interfere with the FM portion.

My experience is limited but, when I investigated it, my next choice was the ASP-9, but it would likely require a rotor.

Magnum Dynalab Ribbon antenna works very well. Godar also is a good choice.

Set up a room aerial inside your attic, if you can. It sounds like you don't want the hassle of mounting it to your roof (or maybe you can't if this is a condo, or you're renting the house). But the attic is close in performance to the roof, and no indoor aerial in our listening room is probably going to touch a attic or roof mounted aerial. Radio Shack used to have a FM aerial for $20 that you could use. On the upside, there will be no ugly aerial visible from your room or from the outside.

happy hunting!

Aaron