Don't count yourself out with JetBlue MC-- I was approved with a score in the 600s in December 2012 and also with a nice limit (intially 5K which I moved 2K to a Barclay Apple Rewards Visa). Barclays is a strange beast who takes into account income, other accounts paid as agreed, number of inquiries, and number of baddies.
I would research the topic here, go to Credit Pull board to see average scores for your area, then pray about it and if you still feel like applying, go for it!
All the best to you! 
PERSONAL: AMEX Platinum- NPSL / AMEX Gold- NPSL / Macy's AMEX Card- $4,500 / SavorOne- $500 / PenFed Gold Visa- $5,000 / Venmo Visa - $20,000 / PayPal MC- $20,000 / PayPal Credit- $1,700 / NFCU Visa Signature cashRewards- $5,800 / AMEX Delta Platinum- $4,200 / NFCU More Rewards AMEX- $3,400 / NFCU Cash Rewards- $4,000 / Credit One Platinum Visa Rewards- $1,000 / Discover IT Chrome- $1,000 / Capital One Venture- $3,550 / AMEX Cash Magnet Card- $1,000 / Belk MC Card- $800 / Citi Shell Mastercard- $400 / Credit One AMEX- $800 / Capital One Spark- $700 / Capital One Platinum- $300 / Citibank Shell- $400 / Oportun Visa- $500 / Fifth Third Bank MC- $300
BUSINESS: American Express Business Platinum- NPSL / AMEX Hilton Honors Business Card- $3,000 / AMEX Delta Platinum Business Card- $3,000 / Marriott Bonvoy Business Card- $3,000 / American Express Business Gold- NPSL / American Express Business Green- NPSL / Sam's Club Business Mastercard- $20,000 / Floor and Decor Pro Premier Business- $20,000 / Phillips 66-Conoco-76 Business Gas Card- $5,000 / Walmart Community Credit Line- $5,000 / Fuelman Mastercard- $3,000 / Amazon Synchrony Business Credit Line- $5,000 / Lowe's Business Credit- $5,000 / Office Depot Commercial Credit- $2,500 / Tractor Supply Company Business- $1,500 / Citi Exxon/Mobil Business Gas Card- $3,000 / Speedway Business Mastercard- $4,500
