Usually in June or July I'll start grabbing stuff as I see it. I find I buy better presents that way. Not only is there less of a financial burden at one time, but I can find things that will actually be meaningful.
I find that women are much easier to buy for than men. I just try and find items that have some shared meaning. Sensitivity and thoughtfullness--pretend ya have some, that's what I always say! Men present a greater challenge if only because most of my friends already have every toy/gadget a guy could want.
This year my greatest challenge has been Christmas cards. With my acceptance of e-mail as a daily ritual, I find that being a more prolific communicator has it's downside. Wheras previously there might be some actual content in said cards, this year its like, "hey, its Christmas so have a merry one and all that shiznit, and I'll type at you tomorrow"...