i would:

- Make Google Checkout free indefinitely for charity and open source donations. You could even go as far as multiplying the donations for some charities and open source projects.
- Create a public personal landing page for every Google account. Consolidate the profiles of groups, co-op, blogger, orkut, calendar etc. and display a link from Google Talk. Like a combination of the Google Account page and personal homepage.
- Improve the Picasa gift-cd, currently you can only place a few albums onto a cd and when you import it you get one big batch. The gift-cd should be a light-weight version of picasa and importing should preserve all the albums, tags and other settings. This could become a very nice way to spread Picasa and thus Google.
- Seamless integration with other IM-networks within Google Talk through virtual jabber transports. Currently you can do somebody%hotmail.com@msn.jabber.server, but that isn't very handy. Google could provide jabber transports which can be activated for certain e-mail addresses (like @hotmail.com).
- Team up with domain registrars to make Google for your domain easier, or let people buy domains directly from Google (and using sub domains might also be a good idea).


Smaller ideas
- Implement micro-payments into Google Checkout (with no accompanied credit-card transaction), also handy for open-source donations.
- Let users record video's directly from video.google.com, this can be achieved through flash.
- Let users record audio in Gmail, e-mail voice messages (also via flash).
- Let the storage counter of Gmail run a bit faster. It should have hit 3 GB a long time ago. Press coverage for every GB!
- Let Picasaweb behave more like picasa by introducing search, tags and the ability to make small corrections.
- Add a 'store attached images into Picasaweb' to Gmail.
- Store files send via Google Talk in Gmail (as attachments of the conversation).
- Integrate google answers with groups
- Support for Live gps input on Google Earth

Trumping (aka copying)
- Trump Microsoft with auto generated 3d textured buildings.
- Integrate search into Google talk (like messenger)
- Locate me of Microsoft's Live local

Not really feasible but cool
- Webcam/audio support in gmail/talk (via flash).
- Google Talk everywhere, the web-based Google talk interface should work from all Google services. This is of course not so easy to implement because the entire Google interface should then be using ajax (a page can never be refreshed).
- Create a linux live cd with picasa, google earth and developer tools for google api's and frameworks.

No-brainers (and probably already in the making)
- Send Gmail sms invitations in more countries. Google currently supports more countries with the sms service voor Google Calender.
- Place a 'Start Menu' everywhere, this button/menu can be used to navigate through Google's services and should be available from all of Google services.
- Google login for youtube
- Integrate Spreadsheets + Docs into Google Apps for your domain
- Implement Google-look for orkut

Oldies (from my 2005 predictions)
- Webcam support in Google talk.
- Search within Gmail attachments. View attachments as html was of course just step one.
- Buy stuff in the google-shop with your addsense profit (nice for bloggers with only a small profit).
- Import pop-mail into gmail.
- Import old outlook (express) e-mail archives into gmail (like gexodus).
- Skype-in/out functionality for google-talk (dark fiber anyone?).

It seems a pipe in the internets is broken: