I've been through a few reinstalls of Windows Vista. Here are the first 10 things I do to tweak things to my liking. Hopefully someone else out there can use a few of these

1. Get your display resolution set up the way you like
Start orb -> Control Panel -> Appearance and Personalization -> Personalization -> Display Settings
- Move slider to your desired resolution
or click the Advanced Settings button -> List all modes -> Choose your desired resolution and color depth

2. Turn off annoying sounds
I just don't think start up and shutdown sounds are necessary. Especially if you have a laptop and are prone to using it during a meeting or other quiet place.
Start orb -> Control Panel -> Appearance and Personalization -> Personalization -> Sounds
- Change Exit Windows to None
- Change Start Windows to None
- Change Windows Logoff to None
- Change Window Logon to None

3. Set up your start menu and taskbar
Start orb -> Control Panel -> Appearance and Personalization -> Taskbar and Start Menu
Taskbar tab
- Deselect Lock the Task Bar

Start menu tab
- Click the Customize button next to the Start Menu selection
- Check 'Printers'
- Check 'Run command'
- Deselect 'Use large icons'
- Under system Administration Tools, select 'Display on the All Programs Menu'

Toolbars tab
- Select 'Windows Media Player'

4. Set up your views
Start orb -> Control Panel -> Appearance and Personalization -> Folder Options
View Tab
- Select 'Display the full path in the title bar (Classic folders only)'. This will display the path on the task bar and when using Switch between Windows (alt+tab)
- Deselect 'Hide extensions of known file types'

5. Turn off the Sidebar
The sidebar is fancy but I don't want to give up the screen real estate. Plus, if your system is a bit under powered for Vista, you don't need bells and whistles running.
Start orb -> Control Panel -> Appearance and Personalization -> Windows Sidebar Properties
- Deselect 'Start Sidebar when Windows Starts'

6. Adjust power settings
By default, Windows Vista power settings are set to 'Balanced'. This is supposed to be a nice mix of power saving and speed. If you have a desktop or are always plugged in, why not get all the power you can out of that expensive CPU?
Start orb -> Control Panel -> Hardware and Sound -> Power Options
- Select 'High Performance'
If you want to go further and set your own parameters for power, click 'Change Plan Settings'

7. Tweak system performance
These next tweaks will maintain a nice look for Vista yet get rid of the cpu cycle dragging overhead of animated windows and menus.
Start orb -> Control Panel -> System and Maintenance -> System
- Click 'Advanced system settings' under tasks on the left
- Click ok to allow your permission
Advanced tab
Visual Effects tab
- Click Settings button next to Performance option
- Deselect all boxes except:
'Smooth edges of screen fonts'
'Use drop shadows for icon labels on the desktop'
'Use visual styles on windows and buttons'
Click Apply
Click OK

8. Reduce the size of those desktop icons
Right-click on desktop
Under View, select Classic Icons

9. Turn on network traffic animation
I like the new networking icon in the task tray. It has a world on it when you are connected all the way throught to the Internet. So say your router is down and Internet connectivity is down you'll know right away because the globe is gone. Another nice thing that is off by default is having your network icon animated to show that traffic it going through it.
- Right click on the network icon in your task tray
- Click 'Turn on activity animation'

10. Set up OpenDNS as your DNS servers
A personal preference and not so much a windows tweak but I'm having good results using OpenDNS as my DNS servers rather than the ones my ISP provides. If you are behind a corporate firewall the depends on domain authentication, proceed with caution because if you replace your DNS servers you might not be able to log into the domain.
Start orb -> Control Panel -> Network and Internet -> Network and Sharing Center -> under Tasks on the left, Manage Network Connections
- Right click on the icon representing your network card
- Click Properties
- Click Continue
- Click 'Internet Protocol Version 4'
- Click Properties
- Select 'Use the following DNS server addresses'
- Primary address is 208.67.222.222
- Secondary address is 208.67.220.220