>>>Lucky you. We has such set up (64-bit) and were getting SQL Server messages about memory not been available and SQL Server would freeze for a while because Windows would use it's swap file at that time.
>>>We had to upgrade to Windows Server 2008 to resolve it. I think there's MSDN KB article about it http://support.microsoft.com/kb/918483.
>>
>>On the location I have SQL Server 2008 installed on Windows Server 2003, this is not the 64 bits version.
>
>It's applicable to 64-bit version only

I got SQL Express 2008 on 64-bit WS2003, and it's fine - never had such a problem, though maybe once a week I need to restart the Express. It tends to take up a lot of memory when I do some gigabyte sized operations over larger databases, so this helps the speed but isn't really necessary. OTOH, this is not a real life example, I'm alone on that server.