Some people are using

Ultra Sparc 10 - for small databases
E250, E450, E3500, E4500 - for medium databases
E6500, E10000 - for large databases

but again it depends on your definition of the size of the database and the number of concurent users, number of transactions, etc.


Hope that helps,

clio_usa - OCP 8/8i/9i DBA