What to look for when purchasing a blender? I currently don't have a blender after purchasing my own home and am looking to get one for making smoothies primarily, but also for pureeing for soups, etc.

I had a smoothie maker that I won as a prize; it was very obviously a cheap unit. It barely handled frozen fruit and yogurt. Ice cream and frozen fruit burned up the motor.

I am aware of the extreme "Home Improvement"-style "Binford-3000" Blendtec blenders (also as proposed in this question) but they are extremely expensive and I don't plan on incorporating cell phones or garden rakes into my smoothies.

What should I look for to get a quality blender? I don't want to purchase an inexpensive one three or four times in the next few years. I'd prefer one that will last a long time and prove to be a good kitchen tool.

Edit:

In shopping for blenders, it seems that most seem to be between $30 and $150. Obviously there are some questionably cheap ones and many that exceed that range. So for the purposes of this question, assume that range to be the budget.
Look for a strong motor and thick blades. If the blades are thin, they're likely to warp over time. The motor needs to be able to spin those blades through the liquid.

Look for a thick glass container. The plastic ones are unlikely to deal with the heat of things like soups and sauces being dumped in.

Check the gasket between the glass container and the piece that attaches the blades. A thin, flimsy gasket is likely to start leaking before a thicker, softer gasket.

Look at the number of teeth on the connection from the motor to the blade. The more teeth, the greater the surface area being used to distribute the power to the blade mechanism and is less likely to wear out.

Overall, as with many things, one of the quickest ways to tell a good one is to weigh them both. The heavier item is better. No one pays for shipping extra weight unless it's there for a good reason. 

(note that the "heavier" rule doesn't apply to electronics like cellphones/computers, etc. where the cost of making it small is actually higher)