Yes, I would. Not frivolously, mind you, but if my life or the life of one of my children was in peril, then yes, definitely.
The WTS claims that blood symbolizes life. But since when did a symbol have more value than the thing it symbolizes?? Since when is a wedding ring of more value than the marriage it symbolizes?? If a thief gave a loving couple a choice between their wedding rings and their lives... it would be plain STUPID to not give up the rings, no matter how much they cost. They can always be replaced.
The more recent issues I have with blood are those that involve "conscientious" decisions by individual JWs to accept fractions of blood. Basically, they can take every single component of blood, provided it is fractionated, but they cannot accept them as a combination of pre-fractionated components. That's just plain STUPID as well. It's like saying "You can't have apple pie, but it is ok to sit down with separate bowls of flour, shortening, salt, water, apples, cinnamon and sugar and eat them all separately." Give me a frikkin' piece of pie, damnit!!
As far as any risk of contracting HIV or Hepatitis or anything else from blood transfusions, I also donate blood (in fact, I will be doing that tomorrow morning), and know that my own blood is safe for others. If I had ANY reservations about whether my blood was safe, I would NOT donate. In Canada, there is no "reward" (ie, monetary compensation) for donating blood, so I think that eliminates a lot of people who have a solely mercenary interest in donating blood. I'm also confident that the screening measures that have been implemented to check for HIV, Hepatitis, "mad cow" disease, etc. are effective and up-to-date. Just as there is risk in taking ANY type of treatment - people can have allergic reactions to something as simple as Tylenol - there is also risk in accepting blood transfusions. You just have to weigh the immediate risks and benefits against the long-term risks and benefits. I'd take another 15 years or so with Hepatitis or HIV, and see my children grow up and have children of their own, than miss out on graduations, weddings, and other happy occasions.