What a difference a year makes. Last year at this time, I dueled the bull case for Amazon.com (NASDAQ:AMZN), when Amazon's metaphorical blood was in the streets. (I lost that duel, too!) This year, I fall on the bear side for this Internet giant.

It's not that I don't like Amazon.com for the (very) long term. I do, actually. It's just that I'm of the opinion that it's looking pricey right now, and I believe investors should wait for a much better point of entry -- and I have a funny feeling it'll come.

I recently pondered the utter change of heart investors can have in such a short time, because Amazon is surely an excellent example. Last year, investors didn't want to touch Amazon.com with a 10-foot pole. This year, they just love the stock. They love it so much it's up 176.7% over the last 12 months.

Short-term uncertainty
Amazon.com has certainly proven that it can impress. In July, Amazon investors were treated to a stellar quarter, showing that unlike many traditional retailers, Amazon's not just about Christmas, giving people even more reason to fall in love with the stock. Of course, investors have to bear in mind that any Internet company worth its salt will always go through investment phases, when it must pour money into new products and services in order to compete and grow. Becoming complacent in the evolving Internet space is a huge risk to any growth-oriented company.

Meanwhile, Amazon's also got many new products that may or may not add up to financial success, and many of them take on already entrenched competition. For example, Amazon recently said it's taking on eBay's (NASDAQ:EBAY) PayPal by offering its own payment system for use on third-party Web sites. That's nice, but Google (NASDAQ:GOOG) has also tried that with Google Checkout and appears to have made little leeway against PayPal thus far.

There's Amazon's Unbox, but of course, it's got some formidable rivals -- like Apple's (NASDAQ:AAPL) iTunes. Meanwhile, whether Joe Consumer is really ready to join early adopters and download movies, giving up on services like Netflix (NASDAQ:NFLX), remains to be seen. And speaking of Netflix, streaming video seems like it might suffice for many Internet users who might not want to deal with slow download speeds or increasing the storage capacity on their computers. Last but not least, teaming up with TiVo (NASDAQ:TIVO) to provide Amazon Unbox services has its charms, but just how much traction that will give Amazon is another question. After all, TiVo has had a very difficult time competing with the cheap generic DVR boxes provided by huge cable companies. TiVo may be the cleverest horse, but it's not the strongest horse in the DVR space. (However, longtime Fool Rick Munarriz did view Unbox via TiVo as a coup for Amazon.)

These are all nice, perfectly logical ideas, and many, like digital downloading, do represent the future of media, but it remains to be seen how well they actually do with mainstream consumers -- in the near term, anyway. There is still plenty that needs to be ironed out, and I'm not sure that many mainstream consumers are ready for the learning curve yet.  

Patience, grasshopper
I'm still a big believer in Amazon's services -- you can find just about anything you want, it's quick, it's easy, and it definitely capitalizes on important current trends like the Long Tail theory of commerce, not to mention social elements including user ratings, recommendations, and reviews. I'm a completely happy, satisfied Amazon.com customer, and I use it all the time (in fact, much more than I should, judging by my pocketbook). Amazon's a stock I owned years ago and would like to own again someday. But ...

... It's pricey. You've probably guessed where I was going with this way back in the beginning, when I brought up the fact that Amazon.com shares are up nearly 180% in the last 12 months. That's just a year after investors seemed to hate the stock. Call me fickle, but the market's clearly more fickle than I am.  

Given history, I have a hunch that another time will come when investors will flip out about Amazon's tendency to sacrifice profit margin for volume. The company will be spending on growth areas, Jeff Bezos will announce initiatives that sound nutty and that nobody believes in, and the stock will suffer a temporary discount once again. Those who own Amazon for the long term should most certainly be content to hold this stock -- but when it comes to planning a purchase, I think investors would be far more prudent to wait for another day, when Wall Street's seemingly love/hate relationship falls more to the negative side.

Wait! You're not done with this Duel. Go back and read the other arguments, then vote for a winner.

Amazon.com, Netflix, and eBay are Motley Fool Stock Advisor picks, and TiVo is a former Stock Advisor recommendation. To find out David and Tom Gardner's latest picks, take a 30-day free trial.

Alyce Lomax does not own shares of any of the companies mentioned. The Motley Fool's disclosure policy has a full pocketbook.