Personally, I'd choose one that

. . really interesting, I agree with Des: don't write a character from a canon you don't feel you know well enough or don't feel you could get around not being a complete expert in by careful research. For example, I have a Klingon agent, but while I know Star Trek pretty well, a lot of the material on Klingons and Klingon society is in the series that I haven't seen very much of. Since my Klingon is from the original series (which I have seen), I rely only partially on my memory of TOS, which is mainly outsider POV anyway, and make sure to boost my knowledge with close reading of the Memory Alpha wiki articles on Klingons. I wouldn't consider myself an expert on Klingons...but I do feel confident writing one!

That's not to say that research doesn't apply even with characters you know more about. I also look at wiki articles for Vulcans (T'Zar) and Time Lords (the Reader), though not as often since I know and remember more about them without the extra research. Elves probably get the most infrequent amount of extra research, if you take out anything to do with researching names, looking up bits of languages, or checking bits of history.

Basically, writing characters from canons that provide anything more than 'this is its name, its function, and the basic way people react to it' will generally involve at least a little bit of research at some point. How intense or intensive the research gets... well, that's up to you and it's up to the canon. Also, your memory of the canon.

So yeah. Feel better, and also don't worry about how frequently you're on or off the Board--people tend to drift in and out a bit, especially around exam times. We'll often give a warning if we're about to disappear for a month or so and know in advance, or do some sort of welcome back post if it's been a long while since we were last on (or even a returnbie post, if it's been a longer while), but generally speaking, things are fairly casual.

So don't stress about how active you are or aren't able to be. Just focus on getting better :) As you can see, we're still here!

Also, hurrah, one month anniversary! *throws confetti* Did you know that in Italian 'confetti' actually has something to do with almonds? Sergio Turbo can tell you more, if he's around...I, unfortunately, have forgotten and am not Italian.

Good luck with the agent!

~DF

Two of them, actually.
1) If you think it's OP or too undefined, it is, and you shouldn't be using it in your PPC writing.
2) If you're not sufficiently confident you can write an agent without having embarrassing canon-related slip-ups, don't.