Define What Is Important
Before you can determine which machine is best for you, you will need to list out those features you really want. First, do you want a top loader or a front loader? Front loaders are considered to be better machines (clean clothes more gently, better, and use far less water to do it), but you tend to pay more (sometimes way more) to get a front loader. A really good top-of-the line front loader (like the Whirlpool Duet or the Kenmore HE4) will cost between $1,300 to $1,500. On the hand, there are smaller front loaders that can be had for under $600. Keep in mind that if you do lots and lots of laundry, you can actually save over $100 a year runing a front loader rather than a top loader. If you do only two or three loads a week, you probably wouldn't save all that much.
Options for Front Loaders:
Stainless Steel washing tub
Really large capacity (3.5 to 3.81)
Internal water heater
Sanitize Cycle (not all machine with water heater will heat to sanitize)
Really fast spin speed (1,200 is considered very fast)
If you are going with a conventional top loader, a top of the line machine can be had for under $600. A basic top loader can be had for under $300.
Once you have started to focus onto specific machines, you may need to go to a large forum to read about specific machines. Check out "ths.gardenweb.com" They have a laundry forum that has tons of postings on all the various washing machines.
Good luck.