How to decide optimum type

Hi,
I use sql server 2005. I want to store values into a field. The values are floating point numbers. A value in the field can only be in the format of #####.### like 12345,678.

So i want to learn which type i should use for this field to provide better performans and memory improvement. Should i use decimal(5,3), float, number or anything else?

re: How to decide optimum type

Depending to a number of factors, including max and min value of your content, the number of records of your table, to assess your table size, etc...

You can start from here

Good luck!!

-- CK