I've read the other posts about getting hacked. Most people suggest "security widgets" then there's usually a lively discussion afterward about "oh, don't use this one, it gets targeted all the time"

I would really like to understand something before just installing it.
can anyone list some good ones and what they do?
and if you don't like some, can you explain why?

My site was hacked.
Webmaster says the virus/hacker may have come in through blog comments -they think someone left a malicious script in the comments that stayed on the site after the comments were deleted. is this possible? we were using Disqus for comments. Is there a better one that is more secure?

I'm using wordpress.
to anyone asking, I am not using hostgator.
yes, all my passwords for EVERYTHING have been changed. I'm looking at how to keep this from happening again.