I love Amazon. The shopping experience is great. Product description and reviews are very good resources. Prices are, to say the least, competitive. The customer service is very good, if you bought "ships from and sold by Amazon.com".
I do most of my shopping there. And fairly or unfairly, it worries me. I make it a point to use shopping alternatives when I find ones that are equally good. Let me share two of my favorite alternatives:
1. Frys: They match Amazon's prices. I wish more retailers did this.
2. Newegg.com: Every bit as good IMO. I find their product reviews more useful than Amazon's and I can't say this for any other retailer.
Please share in comments if you know of other alternatives.
This post is partly inspired by comments on recent HN posts, where people expressed similar concerns about Amazon becoming too powerful an entity.
EDIT: minor formatting