I just found some time to install VS2008 at Home, as well as running WindowsUpdate etc.
After a few restart, install is done and I run services.msc just to make sure everything is alright. At there, I found that "Windows Event Log" is not starting.
I started to start it manually, and got error message "Error 5: Access is denied."
I fired up Sysinternals' Procmon.exe to check, and found it have trouble opening "%windir%\System32\winevt\Logs\System.evtx".
Having checked the service runs in "Local Service" account, I granted read/write access to files in this folder, and the service started successfully.
Checked G**gle and see there's other people experienced similar problem but cannot find a solution, I decided to post it here. And also hope the others see if there's other consequence on granting the access to the account.
P.S.: I compared the folder to the raw installation(Jan 2007 DVD only, patches not applied) image of Vista (I created one immediately after installation after my last reinstall) and found this folder does not exist on that copy. So this ought to be something new.
P.S.2: After successfully started the service, the system seems runs significantly faster.