Couple of the issues i had faced recently
DataKeys sent automatically to storedprocedure
if you are using SQL Datasource in any of your data bindings, and if you are trying to do any db operations- the datakey field is automatically sent to the stored procedure you are using to do the db operations. this means, whether you want or not the (first) parameter in your stored procedure should be your datakey.
This is pretty cool if you already knew this or pretty awful if you had to try to figure it out for atleast an hour.
SQLDatasource Controlparameter and the table Null Value problem
if you are basing your query on a user entry in a textbox, you might sometimes want to display all the records if there is no entry in the textbox.(if there is no validation). This simple things did give me and probably many more developers a tough time. What complicates the issue is there is an option to set the default value to be null, which does not seem to take care of the problem. Hannes Preishuber offers a neat solution.(thru Doug Reilly)
Also i found/experienced/heard about this weird sql2005 bug. SQL2005 server cannot be started/connected through remote desktop in a windows xp machine