Apartment Therapy recently blogged about grown-up solutions to toddler clutter, which is a constant battle at our house. My solution to this is two-fold:
1) Resist the frequent impulse to buy toys for Sophie whenever we go out, and
2) Large straw baskets in every room. I throw all her toys into these baskets every night before bed. During the day, they're accessible enough that she can get her toys out herself.
Done and done.