Here's my 500w 36v Front Wheel Cannondale F4 Conversion.
I did a lot of reading here and on Pedelecs and got lots of helpful information to help me with the build.
Some of the members on here have some serious knowledge and a lot of information went straight over my head but i ended up with a very useable bike which I'm very happy with. It's a cheap Ebay 500w conversion kit with a second hand 36v bottle battery also from ebay.
Cost of the kit and battery was about £250.