Do you live in an apartment, or in a house?
Truth is, if you live in an apartment, I'd suggest just getting a home-theater-in-a-box and calling it a day. The Denon looks pretty good, though there are probably many options, many even cheaper than the Denon system, that will work well enough. In my opinion, home-theater in a box systems can often be a good value for the non-enthusiest, and with that in mind, there are lots of $200 systems that are plenty good for most peoples needs.
If you live in a house, (some space between you and neighbors), then I think you should try to indulge a bit and build up a system from a receiver, floor-standers, bookshelf's, and center channel, very much like what you have linked to there with the polks and the yamaha.
When picking out receivers in the budget range, I am of the firm belief that you should pick the unit based on the inputs/outputs you need, and the interface. Yamaha makes good stuff, but many people hate the orange LCD displays because they are hard to read. As it turns out, most of your major brands in a box store (onkyo, sony, panisonic, kenwood, pioneer etc) in the budget range, are all acceptably "good" IMO. Take things into consideration like the controls, the remote, the button sizes, button labeling, the ease of use, and the settings you want/need for certain applications. We have a relatively inexpensive receiver in our living room for home theater/tv related stuff. We went with an Onkyo (rated "65W" /channel) because we liked enough of the interface/layout etc and, well, it sounds fine too (they all sound fine to most people, and the ones that don't can't usually be adjusted to sound fine anyways.)
As far as the sub is concerned, if you are in a house, especially if it's in a large room, the bigger the better. You're on a budget so I'm not going to go into the details about quality and crap here, just keep in mind that bigger is a simple solution to better if you are trying to really feel your base in a large room.
Regardless of what route you decide to take, if there is one thing that I hope sticks with you in this purchase decision, please remember the following: WATTS DON'T MATTER. Do not compare systems based on watts, they are meaningless figures. The truth is that none of the budget units can deliver their rated output cleanly anyways, and more importantly, that doesn't matter, because you will never need that many watts anyways. Most of your listening will occur at anywhere from a fraction of a watt per channel to a few watts per channel. The "Big Watts Game" has been going on for years, until the consumer realizes that wattage is the least important specification on an amplifier, they are going to keep using it as a sales gimmick. Don't fall for it.
As far as speakers are concerned. You should go into the listening room at best buy and swap around between various speakers for a bit. Don't worry about claims of wattage handling or cool looks or cone materials, those things don't matter. When selecting a budget speaker, what you are doing, is selecting the one with the characteristics that please you. No budget speakers are going to be all that flat, nor are they likely to produce an extraordinarily transparent sound stage, but by comparing the same source material on a hand full of them, you may be able to find a set that reaches out and touches you a bit differently. Some speakers are very forward and aggressive sounding, some are very laid back, some are boomy and some are twangy. Almost any of them can be equalized to sound similar to another speaker anyways, so it doesn't matter a ton, but might as well find a set that sounds alright to you. Also, if it's important, consider aesthetics, especially if you are married
Best of luck in your decision.