I lurk a lot on writer forums. Actually I just joined one called The Writers Chronicle which seems lovely, (thanks for the invite Emily!).
So on these forums I've often seen the question come up, "Do we unpubs really even need an agent?" And I answer, or actually I don't because I'm lurking, but in my lurky mind I think to myself, "Yes!" But maybe not only for the reasons you think.
Sometimes I pull out an old ms of mine and wonder...if I re-revise could I make this thing work? And I'm not talking about my very first ms (which I really promise I'll never query. Sometimes I think I should burn it just to be sure no one reads it. Ever). I'm talking about those manuscripts I'd put aside in the spirit of keep-moving-forward and all that jazz.
And if I did that and even one person seemed a tiny bit interested I might end up revamping the whole story and sending out a few queries (I tend to only send out to a few agents at a time. Maybe that's my problem. I should query the masses!).
By this point I might wonder, should I really put some energy into the old girl? Or stick to revising the one I just finished? Or start the next one that I've been plotting? Maybe I can do it all! It's like juggling, just throw in another bowling pin, I'll keep my hands moving and it'll be a great show!
So here are my thoughts: Besides having an agent for "selling" the book and all the contract stuff, it would cool to have advice from someone who really knows the market and can suggest where I should put my enthusiasm and where I should find an empty spot on my bookshelf.