I've been tasked with making a powerpoint theme for the company I work for and one of the requirements is that it uses a font that comes standard with most computers. What are some of the built-in sans serif fonts that graphic designers respect and use more frequently?
Of the original "web-safe" (that is, as close to universal as you'll get on the Web) sans-serifs (Arial, Impact, Tahoma, Trebuchet MS, Verdana), Verdana tends to get the most love. It's well-designed and is designed to be readable on the screen. It was designed by Matthew Carter, a respected typeface designer, and the design itself is pretty original, so it doesn't get panned for its existence and history as much as Arial does. Also, MoMA added it to its design collection, calling it (and the others in the collection) "a milestone in the history of typography". A scientific study (funded by Microsoft, so take with a grain of salt) touted Verdana's readability, particularly at small sizes. It was one of the first fonts that was designed with readability on the screen particularly in mind, so it has a large x-height (good for seeing the lowercase letters) and is well-hinted. These advantages will become less relevant as pixel density increases, but they're good things to look for in a screen font for now.
Arial is almost universally panned by designers (see above link), Impact isn't practical outside of headlines, and even though Tahoma is more or less Verdana's skinny brother, it doesn't tend to draw as much praise. I've personally never minded Trebuchet as a choice, but it doesn't seem to be as common.
If you're using Office 2007 or later, the ClearType collection comes into play. Three sans-serifs are available: Calibri, Candara, and Corbel. Everything I've read about and them adds to my personal opinion - they're good fonts to use. Wikipedia told me that "Calibri won the TDC2 2005 award from the Type Directors Club under the Type System category."
If you have the right version of Publisher (ours was 2003), there are some extra fonts available. I'm not as knowledgeable about this, but I know that Publisher was the reason we ended up with Franklin Gothic on our PCs, and that is an excellent choice of a sans-serif.
I'll add a disclaimer - as John notes, you can embed fonts. If a font is not embedded, you're always at the mercy of someone else's system, and no font has 100% saturation everywhere.