You can be whoever you want to be, even without a transition. It's still possible to have a happy life, to find someone to be with who accepts you for who you are and not be concerned about whether there's an "F" or an "M" on your birth certificate.
Since I'm someone who has been there, done that, I'll tell you what the advantages and disadvantages I've found are.
Advantages
No drama - family, friends, workplace, etc - and really, you can still "come out" to people and tell them who you really are, but if you're not going through a transition there's a hell of a lot less drama about it.
There's also the prejudice factor you can usually avoid - there's plenty of people who can not hang with people even being gay let alone being trans. Only people you choose to know that about you can be in on that one. The rest of the world never needs to know.
Legal stuff - so much easier to just not have to deal with IDs and whatnot. Although, you still could change your name if you wanted ... people do that kind of thing all the time. Also, if you happen to be gay/bi, you can legally get married to another dude and no one even bats an eyelash. heh.
You can still dress however you want - go ahead, buy men's clothes and wear them. Plenty of people don't even pay attention really to that sort of thing. Unless you're hanging out with a bunch of female fashionistas you really got nothing to worry about. Hell even women's clothing can get a lot like men's ("boyfriend" shirts and jeans anyone?). You can even bind and pack if that makes you feel better.
Plenty of times gender doesn't come up at all - especially if you go ambiguous, people will often not say he/she if they don't really know. If you are referred to as female, that's just someone else's outside perception of you. If you're cozy with who you are inside, it really doesn't matter if people think you're a women or what. Hell, last time I went to the DMV to get a new picture on my license no one referred to be as "she" the whole time I was in there. Really the only time I get an occasional she/her is in a retail type environment.
Disadvantages
You'll probably never be able to grow a beard.
You're never going to have a perfect, functioning penis (even if you got surgery - until they can grow those things in labs and make them bio-compatible, trans guys are screwed and not in a fun feel good way!)
A lot of society will not see you as male (unless of course you go ambiguous and then you can have some fun confusing some people).
If you're straight, you won't be able to marry the girl of your dreams very easily.
There will always be situations where you'll have to "fall back" on the female identity. But as I said above, if you're cozy and confident with who you really are, you can consider this a simple acting job.
If you have serious dysphoria, you'll probably at the very least need therapy or to find some way to deal with it. Sometimes you can find silly small things like wearing men's underwear, binding, packing, etc that help with it and make you feel more comfortable.
So anyway, yeah, I'm a bit different from almost everyone else here and I don't really advocate for one thing or the other, I'm just here to share my own personal situation and story and act as an example that an equilibrium can in fact be obtained without much fuss really (too bad it took me so many years to figure that out on my own!)
