How many Adsense Ads on a page?

Google has a fairly clear policy about how many Ad units you can have on each page but people sometimes still get a little confused about what is allowed so here are Googles guidelines with a brief comentary.
Remember though - before you go slapping up the maximum number of ads, link units , search boxes and referral units on your page - think. Think what this will mean for the visitor to your site. What will the site look like to them? Will all the adverts produce a poor experience for them. It is more important to get the experience right for your user than to squeeze in every last drop of advertising space.

"Up to three ad units may be displayed on each page. "
This means you can have up to three ad units on each page.

"A maximum of two Google AdSense for search boxes may be placed on a page. "
Again this is fairly clear - two search boxes.

"Up to three link units may also be placed on each page. "
Remember that this is in addition to the three ad units that you are allowed.

"Up to three referral units may be displayed on a page, in addition to the ad units, search boxes, and link units specified above. "
Again this should be fairly clear.

Remember that you cant display Google ads or Google search boxes in a pop-up, pop-under, or in an email.