This is a slightly more budget friendly option, which is according to the budget which was just edited in, the Noctua NH-D14.
This CPU cooler keeps temps pretty low, about 5*C higher on an i7-4770k than the NZXT Kraken x61 I mentioned above.
The NH-D14 is an air cooler available here, for 56 pounds.
Pros
- Is an air cooler, and therefore does not have the probability to leak
- Is within the budget
- Is colder than the 212 evo
Cons
- Not as cold as the Kraken x61
- Looks ugly as heck
- Is only 4 pounds lower than the budget.