TESS, a Taiwanese manufacturing company, recently introduced a 7W LED bulb that, at 560 lumens, can serve as a replacement for a typical 500-lumen, 40W incandescent bulb. Tear-down: inside a 7W LED light bulb article shows you what is inside that lamp. This LED lamp bulb holds seven 1W LED packages (a package of multiple LED chips). The HB-LED-driver IC is an MIP552 from Panasonic.
The LEDs have advanced so much that in the future such builb could be built using only one LED. According to Prosessori magazine news article a single Cree XLamp XM led can produce 750 lumens (equivalend to 60W bulb) with 7W of power. 160 lm/W is expected from cool white variants.
For DIY LED experimenters here are some tips:
Home Built LED Lighting article tells the basics of LED light circuits.
Ultra Bright LED Lamp article show a circuit of a ultra-bright white LED lamp that works on 230V AC with minimal power consumption. This circuit uses 16 LEDs and a capacitor for LED current limiting.
Efficient LED power supply has battery backup article shows a highly efficient and reliable design for emergency LED lighting at 3 to 6W. The circuit’s input is 12V ac.
If you don’t want to build the LED driver circuit from components then you can buy a good selection of LED driver modules from Dealextreme.