Forrester's Charlene Liu predicts that MSN will take market share from Google. The reason:
20% of Google users have MSN as their home page. When they discover that MSN search is perfectly adequate compared to Google, they'll find that it's more convenient to search from their pre-set home page than go to Google.com to begin a search.
Charlene's full post is here. She touches on a key theme in search: user behavior is often determined by convenience. That's why control of the browser is ultimately more important than which home page users start from. (They move away from their home page, but a search window in a browser is always there.)