Hi Maria
It's my personal opinion that you'll encourage more comments if you let them appear, and then deal with removing the spam comments, which should be very few if you're using the Akismet spam filter that comes with WordPress - it's the only spam filter I use and it does a terrific job. It just requires an API key which you can get free by signing up for a login at Wordpress.com (you don't need to get a blog there, just a login will do to get you the API key).
As for rude comments, again this is just my personal opinion, but I don't believe that you should censor legitimate comments, even if they disagree with your point of view. The idea is to stimulate conversation, and if people get a sense that you're censoring the comments, they won't bother with commenting and will lose interest in reading what you have to say. I do believe you should remove offensive words (the old "[expletive deleted]" will suffice, or replace some letters with asterisks, e.g f**k).....
The only comments I've ever removed were those that were so far off-topic that they were, in my opinion, spammy (only submitted for the linkback)...which is just as bad as the usual spam....
Lastly, to change the setting, go to Settings > Discussion......remove the check in the box that says "Before a comment appears...An administrator must always approve the comment"
I do hold comments in queue for moderation if they contain 1 or more links - if someone is linking to something I want to know about it before it appears.....
