Proto-Pic - www.proto-pic.co.uk

I have used Proto-Pic a couple of times now to buy electronic components and Arduino shields.

They are not going to rival Farnell for their range of components, but they have a good selection of the core stuff you need on a daily basis, and their kits and microcontroller-related products are great.

The site is well laid-out, clear and easy to navigate, and prices are pretty much as good as you will find.

You'll get emails informing you of the progress of your order and both my orders arrived within a couple of days (I didn't ask for next-day delivery).

Overall, a great site for anyone into microcontrollers or robotics.