asp.net - sql server database design -

i planning create website using asp.net , sql server. however, plan database design leaves me wondering if there better way.

the website serve repository of information various users. figure have 2 databases, membership , profile database.

the profile database contain user data users, each user may have ~20 tables. create tables when user account created , generate key used name tables. tables not directly related.

for example set of tables 2 different users like:

user1 tables - transactiontable_key1, assettable_key1, researchtable_key1 ....; user2 tables - transactiontable_key2, assettable_key2, researchtable_key2 ....;  

the key1, key2 etc.. values retrieved based on membershipid data when account created. result in large number of tables on time. i'm not sure if limit scalability setting database in way. recommendations?

edit: should mention of these tables contain 20k+ rows.

you don't want create set of tables each user, , want these in 1 database. sql server 2008's large capacity tables (note total objects in database), become unmanageable. best bet use 20 tables, , separate them via column user areas. might consider partitioning tables user value, should tested performance reasons too.