It depends on lots of things. Do you have your financing in place already? That is what took the longest time for us...hubby was self-employed at the time and they wanted EVERYTHING, multiple times (monthly bank statements), it was a very long process!
Then when the actual 'looking' happened, that took a long time for us as well. We actually walked through roughly 140+/- a few houses and drove by and nixed another 100+/-. Hubby and I are/were very picky about what we wanted/needed!
When we finally found our house, it took roughly 35 days from putting in the offer and getting handed the keys. Our 1st offer was accepted too, no going back and forth on negotiating the price either. Lots of things have to happen in between those two things, inspections, title searches, etc. Luckily there was nothing wrong with our house on the inspection report/walk through or I imagine the process would have taken a lot longer with all the back and fourths of fixing this or fixing that.
~We were very motivated buyers and I believe we took the very first step, which was going to get financing in the middle of a February and we spent the first night in our completely empty house at the end of August.
So for us, it took roughly 7 months.
***EDIT***
We put an offer in on one other house and were outbid, we were disappointed at the time but the house that we did end up getting was FAR superior in EVERY way. So don't get discouraged if this happens to you too. Everything happens for a reason! ;)