Thanks, that's exactly what I was looking for.
I understand that [R] will send a redirect header to the browser, but what does [QSA] do? Oh yeah, using the index.html to index.php?q=index with the R flag would break the use of mod_rewrite, hahaha.
This flag forces the rewriting engine to append a query string part in the substitution string to the existing one instead of replacing it. Use this when you want to add more data to the query string via a rewrite rule.