"Even the first year investment bankers usually make at least 50k base - and that's the "don't worry about the number you'll make more in bonuses" number."
Don't rely on the bonuses!
I've been in and known of too many companies which work your ass off with the promise of a big bonus, but when it comes time to deliver the bonus they always have some excuse for either giving you a low bonus or none at all.
Many Wall St firms are also like revolving doors and sweatshops, which treat a many of their employees like crap with the rationale that you're lucky to be working there at all. This is especially true of entry-level employees. But if you can tough it out to senior level, you'll probably do a lot better.