Disappointed. Went from M-Audio AV40's to Paradigm Atom. Advice?

I bought some AV 40's as bookshelves for a small living room. They are hooked up to my HTPC with a X-FI extreme music but I only use them for music, no movies. As long as I adjusted the EQ they sounded pretty good. But after a month I got bored with them and got bit by the audio bug. So I wanted to upgrade to something a little better and a bit more "fuller" sounding.

I read as much as I could on the archives and on the net. I narrowed it down to the M Audio BX5a, Audio Engine A5, or a pair of bookshelves with a budget of about 300-400 bucks.

I was afraid that if I got a better pair of studio monitors they would be too unforgiving and too narrow focused. My living room is small and I sit about 8 feet away from the speakers but its still a living room and not a desk/recording setup. So I decided on some bookshelves and a T amp as these might give me an entry point to building up a nice system over the years. And, figured they might be more forgiving if I move out of line with the speakers, like laying on the floor or something which I do a lot.

I think the Paradigms I got from ebay sound good and full range for my needs, but they lack the clarity that the AV 40 monitors have. I can easily tell when I am listening to a higher quality MP3 with the monitors but not the Atoms. The Atoms sound fuller but a bit muffled or lack of sharpness in the highs. It sounds like the M Audios are playing through a better DAC, more detailed and sharp.  I guess this is to be expected with standard speakers vs studio monitors?

I don't need much bass or volume as my neighbors next door can hear the M Audios pretty well when cranked up half way. I just want the best quality and sound I can get (dont we all), and the potential for upgrading component by component would be nice too.

The only place around hear to listen to speaker is Best Buy, so I took a swing with the Paradigms on ebay. My wife is going to be upset if I buy a third pair of speakers and dislike them again--she does't understand. As it stands I need to get rid of the other two already.

I know a lot of folks are asking which monitor sounds better or which speaker etc, but Im not sure if I should move to better monitors or if I'll appreciate the atoms with better DAC, amp etc in the future, or even a better set of bookshelves.