Sql-server – SQL Server 2008 R2 Resource Managment

It is SQL Server 2008 or SQL Server 2008 R2 ?? Because in your question you mention that client want to upgrade from 2005 to 2008 R2 and you're asking about migration from 2005 to 2008. So for sake of answer I am assuming it is 2008 R2

Since you will not be using other services like SSRS,SSAS and SSIS it should make you like a little easy. Some suggestions are,

1. Use separate physical drives for data and log files for all user DBs
2. Separate physical drive for temp db, backups,system dbs
3. Aligned drive partitions (however it should be taken care by itself since you are using Win 2008 R2 but better check 'em)
4. Setup proper auto increment based on your expected growth
5. Proper recovery mode (Full recovery mode is recommended)

Actually you can find loads of tips for SQL Server database server configuration. Following links can give you some help. For SQL server 2005/2008 (but can be used for 2008 R2) Or General MSDN help for SQL Server 2008 R2 Or google for "SQL Server best practices", which can be of different categories like installation, dev, security configuration, administration, migration etc. But I really doubt that you will find all-in-one type of solution somewhere because in most of the cases it really depends on your requirements.

There are other memory consumers outside of the buffer pool. For instance, SQL Server will use memory for worker threads, multi-page allocations, linked servers, extended stored procedures, CLR, etc.

The buffer pool is never going to equate to 100% of memory consumed by SQL Server. It's a common misconception, as well as setting max memory will be the actual max memory SQL Server uses (not true).

EDIT: Here's how I think you could get non-buffer pool memory size. Note: wait for the input of other SQL Server professionals before taking this query as fact. I cannot guarantee that it is absolutely correct.

declare 
    @data_cache_size_mb decimal(12, 2),
    @plan_cache_size_mb decimal(12, 2),
    @total_mem_mb decimal(12, 2)

select
    @data_cache_size_mb = count(*) * 8 / 1024.
from sys.dm_os_buffer_descriptors

select
    @plan_cache_size_mb = sum(size_in_bytes) / 1024. / 1024.
from sys.dm_exec_cached_plans

select
    @total_mem_mb = sum(pages_allocated_count) * 8 / 1024.
from sys.dm_os_memory_objects

select
    @data_cache_size_mb as data_cache_size_mb,
    @plan_cache_size_mb as plan_cache_size_mb,
    @data_cache_size_mb + @plan_cache_size_mb as buffer_pool_size_mb,
    @total_mem_mb as total_instance_mem_mb,
    @total_mem_mb - (@data_cache_size_mb + @plan_cache_size_mb) as non_buffer_pool_size_mb