Like cars and fishing reels, everyone will tell you to buy their favorite. I will only say this...."Buy your mower from a local lawn mower shop"...You will not get the service and help that you may need if you purchase from a Big Box Store or Sears...Shop around and find one that feels good to you. Best thing I ever did was utilize the knowledge and expertise of the guys at the local shop.
Lots of mower technicians on this board with lots of great info and experiences. One thing I learned is that if you give them enough information, they can send you in the right direction.
Always good to tell them how much yard you have and the layout of the terrain, hilly, flat, lots of obstacles like flower beds or trees or swing sets and stuff.