[boothead]

In general the big ones suck and have a boiler room mentality. Good ones in my experience:

Oxford Knight

Functional Works

GQR

Hays (They're big but have been good to work with)

I'll add more as I think of them.

If you're looking for work in finance - you will almost certainly be going through a recruiter.

[ed_blackburn]

Funny. I've had lots of problems with Hays. Cancelling cheques, unenforceable and ridiculous clauses in contracts for example.

The best agencies? None. Don't use them if you can help it. If you have to the smaller the boutique ones tend to be better, if nothing else because they'll have the better clients and more interesting projects.

[jimduk]

I did a quick review of agencies 2 yrs back to use as we started to run out of organic references in London - Oxford Knight, Burns Sheehan, Recworks (Java and grads) seemed decent. Stack Overflow is also worth using carefully