Thanks again for the reply.
My budget of $365 has to include the hard disk too. On the sites I've been looking at (budget uk sites), the prices break down as follows:
0.5 TB ~ $90
DDR3 4GB ~ $25
Basic FM1 MB ~ $75
Basic LGA1155 ~ $75
Case/PSU ~ $30
This gives me ~ $130 to spend on the processor, which for an Intel gets me: pentium G6950 or i3 2100, to go up to the basic i5 will cost $220.
Or with AMD I can get Athlon ii 605e or A6-3670k or AMD Athlon II X4 651 which is the processor I'm particularly interested in.
It seems that at my price point AMD will give me better bang for my buck. It's difficult to justify 25% increase in the cost to got with Intel over AMD, especially as it's always possible with hardware at every price point to just spend another 5-10% and get a lot more, you have to set a budget somewhere and work within that.
I thought that most of the server tasks that I'm interested in are multithreaded, such as apache and MySQL. However I imagine that these can only use one thread per request, so with really low load, multicores wont be as advantageous as it would if there were several requests per second.