The U37 isn't necessarily a bad microphone, however you'll want to get a proper wind screen for it - and that'll add a small chunk ($6 USD to $10 USD) for a decent one. The frequently used wind screens include the DragonPad, which you can buy the U37 with, as with most microphones.
I personally would suggest the Snowball with a decent filter, but I understand what you're going at. Another microphone to look at, which leaves a bit of an easier price on yourself, would be the
Tonor TN12499 and a pop filter. There's a review on the TN12499's page that provides a mic test and comparison to another microphone, as well.
Taking it a direct step to $49.99, you can pick up the
Behringer C-1, which is honestly an incredibly good microphone to compare with, or go with hillkill's suggestion and save up for the
Samson Meteor. You can find one listed on Reverb for $54.99 USD.
EDIT: Whilst you're against headset microphones and pre-installed microphones, I'd still suggest taking a look at the
Sades brand in the case that your headphones fail and you still haven't made a decision.