I don't use the stock "official" Arduino boards for my work. The $18 teensy 2.0 is smaller than any of the stock Arduinos, has more A/D pins than any of them except the Mega, has more memory, more PWM pins, full speed USB serial support and has a more accurate crystal cock instead of a resonator. You can buy them from the designer [1] ($18$16) or from Lady Ada [2] ($20). Sketch loading and restart is much faster because of the high speed USB port.
The FTDI drivers aren't necessary with the Teensy and you can add the Teensyduino [3] overlay to run your Arduino sketches.
The overlay has several high performance features the Arduino core group haven't got round to yet: the A/D is run in high speed mode and the serial port implementation is efficiently interrupt driven on input and output.
So what is the catch? Some hardware improvements I suggest: get the silkscreen right for Arduino nomenclature, move the led from an analog input to a digital pin and build it with the 3.3v regulator on board and a switch (like the seeeduino boards) ditto for the teensy++. I would pay the extra few dollars for this.
If I really have to use the original Arduino form factor (to leverage a useful shield) I use the seeeduino [4] or olimexino [5]. They are compatible, comparably priced and have some handy extra switches, power supply features and break out the 2 extra A/D pins often omitted on other boards.
Links:
[1] http://www.pjrc.com/store/teensy.html
[2] http://www.adafruit.com/index.php?main_page=product_info&cPath=16&products_id=199
[3] http://www.pjrc.com/teensy/teensyduino.html
[4] http://www.seeedstudio.com/depot/seeeduino-v328-fully-assembledatmega-328-p-439.html
[5] http://www.adrianfreed.com/content/better-arduino-alternatives
[6] http://www.adrianfreed.com/taxonomy/term/173