Where is the home located and what do you want the finished look to be?

Home Depot is not necessarily to be avoided but there are stories of questionable install quality.

As long as home depot is offering the simonton 6500 which is a decent mid grade offering..
AVOID at all costs if they are offering American Craftsman or Silverline by Andersen. They are probably one of the lowest quality windows ive ever seen in my opinion along with pella vinyl.

I am in Northern California. The house is what they now call Mid-Century. It faces South. Mmarse1 thank you for warning me about those stinkers. Thank you Windowsonwashington. :) I am also thinking of having a carpenter rebuild them from wood. I realize that is not an upgrade. They windows I am looking at are mostly Millgard and Simonton. All comments are welcome.

Depending on what is failing on the old units and if they are worth keeping, you might be able to go the carpenter route or to get some replacement parts.

The other guys are being diplomatic. YES, you should avoid box stores. Their products range from garbage to middle of the road (simonton), but more importantly saying that there are "some cases of questionable installs" is an understatement. No craftsman worth his salt will go through the subcontractor turnstile that is their " installed services" dept.
Others may have different experience, but this is what I see.

I agree karateguy....