MediaWiki, should I change the URLS?

[chopin2256]

I installed MediaWiki on my site and I have a concern. The URLS are actually very search engine friendly but I am wondering if I can make them any better. This is the format of the urls:

wiki/index.php/Main_Page
wiki/index.php/Space_Have_Underscores

As you can see, the page names have underscores, which are poor, right? Also, the what about the index.php? Should the index.php be taken out like this:

articles/index/Main_Page

I have figured out to get the link to look like this:

articles/index.php/Main-Page

So there is a hyphen. Should I keep the underscores, or should I keep the hyphen since I figured out how to do it?

Finally, I may want to output all the links like this:

articles/index/Main-Page.html

How could this be done in htaccess? Everything follows the same format. The only thing needed to change is the index.php and add an extension at the end of the page files.

[chopin2256]

I figured out how to remove the index.php so disregard everything except the question:

"should I keep the URLS to look like /wiki/Main_Page or /wiki/Main-Page

[jdMorgan]

GoogleGuy is on record as recommending hyphens. They are treated as spaces by Google.

Jim