Meh, I don't know. There's some trade offs. I think about how much I miss doing messenger work all the time. Everything about it. Even the ****ty weather in the winter and early spring. I work in a lab now, and I like it ok i guess, and I have a 401k and benefits etc etc. But I hate being in all day, and the people I work with are generally the "uptight and white", watch too much news types. Security in computer science? Maybe. That's arguable, really. Lots of variables. Computer geeks let go everyday. And if yer work "defines you", Id waaay rather be defined regarding bike/messenger stuff, and not in anyway computer geek. What a soulless existence, IMO. I also don't see how "bicycling as a passion" isn't a possibility as a messenger. I mean, when I was a messenger, I ate, slept, breathed bike stuff. I rarely used my car, even for grocery shopping. Previous to being a messenger, I had always ridden bikes(But not a "cyclist") but being a messenger made me more of an urban survivalist.
But ya know, that's the dividing line. And that's cool with me. There's alot of messengers out there that make it look like a miserable existence. But I've spent many years on both sides of the desk, and I don't think I'll ever miss the side I'm on now. Even when I think of those weeks of 40 degrees and rain, where nothing you do will keep you warm, and the memories of putting on shoes at 7am that are cold and wet, and have been for the last three days, I still miss it.
Decent points. If you have the opportunity to do the job you love, you absolutely should!
But for financial security, there's no comparison -- the one guy said that if you bust your ass, you can make up to $100 in a day. That works out to something like $25000 gross for a year. While you can be let go as a software engineer (or most jobs, really), you're generally earning several times that other figure, allowing you save up a bunch for a rainy day (or early retirement, more time to ride bikes!) if you're not an idiot about it.
It seems like there are more and more wannabe messengers competing for fewer and fewer jobs, and that would stress me a lot if it were my chosen field. Maybe the faddishness has passed again, and the supply/demand stabilizing, I dunno.
I absolutely reject letting my work define me. I really hate that mentality, and if someone wants to break the ice by asking "so, what do you do?" it's often the last thing I'll mention out of a list. Don't get me wrong: I really enjoy my job most of the time, but I'm so much more than that. I'd rather talk about bike-commuting or my love life or wrenching on my old VWs.