Going back to the precursor Mystery Pollster site, I've been a big fan of pollster.com's Mark Blumenthal and Charles Franklin, along with their contributors like David Moore and Margie Omero (just to name a few), and find it invaluable in sorting through the intricacies of the art and science of polling.
One of the innovations on the site is the Do It Yourself graphing function, available to everyone, which I am going to play with today. This is the classic pollster.com Obama job approval, currently at 58.4:
Personally, I like to look at a bit more sensitivity, without the distraction of the data points (I can always go back in and turn them on), so I like to use the 'tools' option to make it look the way I want (more sensitivity slightly affects the numbers):
And did I tell you I really dislike internet polls? Until the universe of internet poll responders reflects my father-in-law, who always votes but dislikes newfangled devices like answering machines and remote controls for the TV, they're not real, so I like to turn them off:
Oh. Look at that. Obama is tanking.
Applying the high sensitivity, non-internet thingie (the graph tells you what's been changed) to Right/Wrong track, you get a generic temperature-taking that's a mirror image of Obama's numbers. Hey, maybe the worse things are, the more people appreciate having an intelligent grown-up in charge.
There's more work to be done on that front, though "state of the economy" looks a bit more positive.
Of course, the point of all of that is to illustrate the ability to remove, say, Gallup and do it again without Rasmussen and see if it affects the numbers (usually not, but, at least it's testable, so when you say 'it doesn't matter', it's an informed opinion.)
For a more dispassionate look at the Zogby internet poll, Rasmussen, Gallup and the Big Picture, see Charles Franklin. I'm also a big fan of looking at all the polls (not just ours, not just Rasmussen, not just Gallup.)
Let data inform your opinion. It's really a good habit to get into.