I want to create automatic posts from multiple feeds but I'm not familiar with Wordpress so could someone tell me which is the best plugin for doing this in your opinion?
Take a look at Carp from Geckotribes. Besides carp, there are several scripts at gecktribes that converts all kinds of feeds to wordpress pages. Carp just handles RSS2. So if you want to convert ATOM feeds, you might need something like grouper. I use carp on my vbulletin forum to display the "Recent blog post" like what digital point does. But its designed for wordpress. And carp is free.
I tried installing the CarpL version to see how it works and it messed up wordpress with errors, so I had to delete it. I just tried wp-o-matic which seems okay but it only posts the intro text as seen in the RSS XML page, do all the autblog type plugins do that or is there any that crawl the entire article and post it?