Hilton HHonors has the most beneficial mid-level hotel status (HHonors Gold) of the chains I frequent. Gold basically gives you a free internet access and club level accommodation/free breakfast. You will also receive some extra points and have access to VIP only rewards (basically discounted awards for multiple day stays).
Normally Hilton HHonors Gold status requires 16 stays during a calendar year. Hilton is, however, offering a MVP Fast Track offer where four stays or nine nights during a 90 day period after registering gives you a Gold status. The status is valid until the end of April of the second calendar year i.e. if you qualify this year the status is valid until April 2013.