Suppose you have two SA 2 offers, you are in final year of Undergrad but with intentions to get a 1 year Master and your desired position for 2012 is in Quantitative Strategy, Trading at aor :
One is in a well-renowned investment bank (not BB, but almost there), a S&T position in the desk you like the most, but doing Sales. If you are lucky, you might network your way through to the desired position, which is in a different city (the team is not based in a major financial center such as NYC, HK or London). The pay is somewhat low.
The other is in a well renowned department at a major central bank (Fed/ECB), for a quant/risk management position, based in a major financial center, with an extremely good paycheck. The job is extremely related to your desired position due to the quantitative nature of the role, but bear in mind we are talking about a Central Bank. Networking posibilities are unknown within the bank.