I've had excellent luck with the Linksys E2000 (
UK Amazon Link)
It's unfortunately a little pricy (UK£ 63.26 = 102.61 U.S. dollars according to Google) and I got it for $69.00 at Best Buy on sale. I live in an apartment, but have noticed that my iPhone connects to the WiFi when I'm stopped at the traffic light on the street outside my building.
I haven't done it on this one yet, but the E2000 supports DD-WRT which allows for manual manipulation of the transmitter power. (
DD-WRT link). As far as bandwidth, I have an iMac and a Synology NAS attached to it, as well as an ATV2, PS3, MBP, iPhone, and cable company DVR connecting wirelessly to it. The N speed is terrific..I'm getting about 15MBPS both directions when reading from the NAS, and between 30-50 directly connected.