New direction

I have been in my current position (as second level tech support) for almost two and a half years and while I appreciate my job and enjoy my co-workers, it is not my end-all job. I've known that the entire time that I've held the position, but I've never been quite sure what to do about it. During that time, I've been "keeping and eye open" for other interesting jobs that I might qualify for, sending my resume out here and there, not really hearing much back besides, thanks, but no thanks.
About a week ago, one of my automated searches presented me with a couple new positions with Northrop Grumman, a company which I had heard the name, but didn't know much else. They were marked as "entry level" engineer jobs, so I decided to throw my hat in and expected the same results as I had previously become accustomed to. To my surprise, I received a call from one of the organizers asking if I could come in for an interview the next day. Later, it was rescheduled for 3 days later... today. After a bit of drama regarding driving directions and date, everything was cleared up and I was there half an hour early, expecting that there was a bit of a mistake and I would soon be asked to leave.
I was brought into the labs and shown around the systems that they use. They told me that the majority of their jobs is to research and develop new defense systems for the Navy that would win new contracts. Apparently they had recently won some number of said contracts, which is why they are currently hiring 10 positions.
I interviewed with a total of 4 guys, all working for smaller parts of the same larger group. Each had questions about what I had done and what I wanted to do. After talking to them, I quickly gathered the idea that getting a position with them would be all I could have dreamed of. This could be my end-all job.
After the interview, the main guy walked me around and started talking about benefits, which included a "medical savings" account that the company puts $2000 per year into, and if it's not used, it will roll over to the next year and after a few years, if I've been healthy and then need a big procedure, it's all there for me to use.
He asked me what salary I wanted and I told him what I was currently making. I said that I'd like to make about that, but would be willing to take a pay-cut as this was the kind of job I wanted (not to mention I'd be getting a security clearance out of it). He stopped me and said, I would certainly not be getting a pay-cut.
He topped it all of by telling me that he thought my diversity in knowledge and experience was impressive, he felt that the interview went well, and he couldn't imagine that I wouldn't get an offer. Well, okay.
Since then, I've been having a bit of difficulty breathing, just waiting for the phone to ring...