Routing is possible using cloudmade or others. But, I think is very important see routing capabilities directly in osm.org website.

I really-really don't care if it won't be pixel-perfect in relation to every two points of the visible map, but it's seriously annoying to not have any idea what order of magnitude far apart the displayed map features are.

Ability to click on POIs and view its data.

Nominatim is the osm geo search engine. We have to improve the presentation of results:
-icons similar to the nominatim page
-filtering for similar objects (e.g. a city, it's boundaries,....)

have a look at: http://nominatim.openstreetmap.org

even in a small towns, the edit history, at least in germany towns a full of bot edits somewhere far away

The current OSM logo does not reflect the technical advancement of OSM. It is a nice idea, but it is time for a new, more professional logo. There was recently a contest for the openstreetmap foundation with excellent entries. A same event should be held for OSM. The current logos has the flare of the early 90s and is not a timeless piece

with OSM logo, search & controls on top of it ...

Integrate openstreetbugs into the main page. This allows ordenary users to contribute without having to create an account and learning how to edit the map.

All those extra infos tagged to ways and nodes are just wasted if not displayed. Not everything can be rendered as icon. If there are opening hours attached to a pub, why not show it in an info field? Please also show coordinates for the cursor position. Possibly even in multiple formats.

OSM is often seen as "the map"
We should show all visitors the diversity of the existing maps (not only the styles but also the data like opencyclemap, OSMC Reitkarte, OLM and much more).
This will show the big difference between OSM based maps and others maps

This shall be visible on the start page of OSM.

it would be great if the design worked for small screens. for example, the current osm.org site is sort-of OK for mobile-sized screens (320 or 480px in width). it would be even better if the design didn't rely on browser identification (which is flaky and a pain to implement), but used standards-compliant methods like CSS media selectors.

Displaying this up-to-date counter will demonstrate to everybody the relevance of OSM
A list of such websites exists in the German wiki (http://wiki.openstreetmap.org/wiki/DE:OSM_Internet_Links). Maybe there are more such lists which shall be put together.

Please implement geolocalisation supported by browser like Firefox. So you don't neeed to use the search or to scroll in first.

Expecially for newbies it is difficult to get in touch with all the OSM stuff, so personal contact and advices is allways good.

For that we need a better tool to see who's active in my town.

Improvements:
-distinguish between registered but inactive/active users
-let the user specify a home area instead of only one node
-see more people than just one mile away (important for huge cities)
-let the user be multihomed
-broadcast messages for a given area (e.g. invitations for mapping parties)
-notification for new registred users for an given area (RSS)

This is useful for POI's which not every users want to see on the map. Example: For a scuba-divers it's nice to see where the spots are where you can go diving and you want to have a map where the spots, parking places, restaurants, bars and toilets are shown.
Also geocacher want to see special POI's in which the average user is not interested in.

We need a central place where users can fast download precompiled map packages for the different major plattforms and tools (e.g. Java ME phone, IPhone, WinCE PDA,...)