Horns for SET: Low budget solutions

Abdou, all of the above recommendations are good ones. One thing you really will have to consider is room size:

1) Large horn speakers with multiple drivers (Altecs, Cornwalls) certainly need space. Not just because of bass, but you have to be able to sit 8-14ft away for the drivers to integrate properly. In a huge room this would be my favorite option.

2) In a very small room, Fostex based speakers are much easier. Without sitting far away you will be able to get fairly good imaging. Good examples are the Hornshoppe Horns and Cain Abbys. Both have enough bottom-end extension to get away without a subwoofer in a small room. Also you can always add a subwoofer later. In my small room the Abbys work like a charm.

Much of the above will come down to a matter of taste as well. You should try to find audiophiles in your area that might let you listen to their system - always a good idea to make friends ;)

I'm in a tiny apt. in Chicago and they'd take up about half of my living room.

In that case I would urge you to consider single driver speakers. The Abbys project a fairly large, life size image that extends forwards. It is much easier to achieve reasonable imaging with single drivers. You won't be able to extract the full potential of a larger horn speaker. If you still want front loaded horns the smaller Heresys would be worth a consideration and an affordable introduction to low-power hi-efficiency amps/speakers.