You don't have to use a service like Typekit to use a pretty webfont. The advantage Typekit has is that it gives you access to a lot of font choices to use (which you wouldn't otherwise have access to) and hosts/serves up the fonts for you. Sites not using Typekit are most likely just using their own @font-face solution and hosting the fonts on their own server (which can also be a faster solution than loading in 3rd…
"Never use fonts and just hope a user might have it." I would question that statement. Specifying fonts a user "might have" is the entire basis of normal CSS font selection. There's absolutely nothing wrong with specifying a somewhat unusual first choice. That's what fallbacks are for! For instance: font-family: "Adobe Myriad Pro", Myriad, Georgia, Times, Times New Roman, serif; Just make sure that you order them fro…
I was thinking more along the lines of having some non standard font on your computer that would differ greatly from a common web-font, specifying that as the top choice in a font stack, and then designing your site using that font. Which I was thinking was essentially the goal of the OP.
I think your font stack example isn't quite as extreme as I was thinking in my head. Even still, your example has two sans-serif fonts that may/may not be on a users computer, with your fall back choices then being serifed fonts. Already, that font stack is setting your site up to present some very different designs to various visitors. That font stack would fare better if it was something like font-family: "Adobe Myriad Pro", Myriad, Lucida Sans Unicode, Lucida Grande, sans-serif;
If you are going to pick a non-standard font to use without font embedding, then your fallbacks should be web-safe fonts that are similar in design and in rendering size. Exotic Font Y at 16px can look much different from web-safe Font Z at 16px.
So, if a very small percentage of your users will have an exotic font installed that you want to use, and you aren't embedding that font for others to use, then you are setting yourself up for design/rendering problems for all of the people who have to use the fallback. It just ends up looking goofy and unprofessional, as well as being a bear to get to render nicely for both varying font styles in a "pixel perfect" design. Font stacks should be about trying to get the same experience across multiple platforms and browsers, not 30% get the best experience and 70% get a crummy degraded experience.