I was thinking, over the weekend, about the way reading poetry works upon the unconscious mind, and then feeds into your own writing. If you're trying to write poetry, than reading as much of it as possible can only be a good thing, as far as I'm concerned - the wider the range of influences you get exposed to the better.
Having said that, I've long been wary of trying to write too soon after reading poetry that I like a lot, because bitter experience tells me that the result is often a series of third-rate imitations of the writer in question. Far better to digest the other poet's work slowly, very slowly, and fully absorb the literary nutrients therein.
Sometimes, though, reading something that's just shout-out-loud brilliant does have an immediately inspirational effect, and the only thing to do is to get the notebook/beermat/laptop out and write. It happened to me last week. I'd been rather stuck on several (largely unconnected) poems for weeks, months even, and couldn't find a way to move forward with them at all.
Then, after reading a particular poet's latest book, I had a blinding-flash revelation of where I wanted to go. I was very dubious at first, but went with it, and have been checking and rechecking ever since that what I came up with wasn't a pathetic retread of their work. I'm pretty sure it's not (although that's not to say it's any good) - in fact, I think it's stylistically a very long way from what I was reading.
So how does this happen? I tend to think that it's simply that reading a great poem reminds you that such things are possible - spend to long looking at your own failures, or even just your own almost-poems, and you start to forget what a real poem is. All of which is a way of saying again that the more poetry you read, the better, because the more likely you are to come across something astonishing, or inspirational.