motorhaven - 10:34 pm on Sep 1, 2013 (gmt 0)
I have found the vast majority of directories are garbage, with all due respect to IncrediBill The link worthiness from them tends to be garbage, along with all the "domain info" and "seo info" sites. There are exceptions of course, and I'm careful to make note of ranges of important thing and punch holes in the firewall for them. Frankly, I work at getting my domains out of many of those, so if they drop my site that's a bonus.
I declare port 80 for the Americas, Eurpoe, parts of Africa and Australia. Most of Asia I block all ports - it cuts down on the noise in my daily server log notification (there's an RBL lookup for email which spits out status).
I use a combination of both. iptables for the vast majority of it, because the vast majority is garbage and not human. Use .htaccess for ranges which are iffy and not 100% confirmed.