Kristmace do you know anything about PC's?
First of all PSU is the most important part so you need a quality piece especially if hes adding a GPU which for all we know could be a 7850 or 7770 later on.
And Llano does not beat an i3 in any way for his purpose. The dual cores on the i3 alone would be better than the Llano chip for video editing because of its architecture but it also has Hyperthreading which makes it more than adequate/.
There's no point speccing a system thats 30-40% over budget though. The OCZ PSU that OCUK has for £29.99 is perfectly adequate and quite capable of powering a 7850.
Llano is inferior to i3, I'm quite aware of that but look at the budget. If you can save £20-30 by going Llano then that has to be considered. Benchmarks on Anandtech for Llano for video tasks aren't streets behind an i3 either.