FM Reception question, please

I have a Pioneer TX 9500 II tuner and have it hooked up to that antenna that is a wire shaped like a "T". Reception is farly good but I thought that I could improve it with an indoor antenna designed specifically for FM. Needless to say, I bought the top of the line Terk amplified indoor antenna and found that my signal was roughly half as good as copared to the wire. I tried alternate positioning and different gain settings to no avail. What gives? Do I have to go to an outdoor antenna to get better reception? Thanks for your interest.
I have a Magnum Dynalab MD-100 tuner. The Magnum Dynalab ST-2 and Fanfare FM2G are very similar. I tried the ST-2 indoors and outdoors (but not at a high elevation) and it was surprising ineffective. I stayed with my Magnum Dynalab Silver Ribbon, which is directional and brought in a stronger signal. I was very surprised at this result. I did not try the ST-2 on a high roof mount, where it should be more effective. So, if you are really committed to staying indoors, consider the Silver Ribbon. Its only $30.
Its remarkable how much ridiculous misinformation is out there. The Magnum and Fanfare whip antennas are junk, and cannot have gain over a simple dipole. They're little more than overpriced wire rods. Real antennas take space, and there is no way around it.

Go to RadioShack, and spend $20 on their 6 element outdoor FM antenna, along with $50 for a rotator and accessories and mount it on your roof if you want decent reception, or mount it in your attic pointed in the direction where the majority of the stations are which you want to pick up. As a backup, keep the dipole and use an A/B switchbox if you desire a station where the real antenna doesn't point.

Beyond that, the simple "T" shaped dipole is not going to be improved upon by either of the two garbage antennas that the scam tuner companies are foisting off on unsuspecting consumers. If you don't mind the ugliness, get a really big antenna like the models from APS or alternately the TACO QFM-9 or Winegard HD-6065. The best FM upgrade I ever made was putting a real antenna up.
Ryanmhl is right on the mark. I have found identical results with a whip antenna and with the $15 Radio Shack omnidirectional antenna mounted in an attic - why pay more for a whip. A tuner with dual antenna inputs is the way to go; try using both a directional and nondirectional unit in the attic or on the roof. It may take a weekend of work, but there is no substitute for setting up a real antenna. If you think whip antennas to be useful indoors, try parking you car in the garage and checking the reception.
Please forgive what is surely a naive question: Why can I get decent FM reception with my $30 boombox or with my cheap car stereo, but nothing with a $400 (or more) FM tuner unless I spend even more money on a stinkin' antenna?

Can someone explain this to me? Thanks!
I also have an FM antenna in my attic. All stations are north, so I don't need a rotor.