IO Analysis

I'm looking to see if I have a issue with excessive IO activity caused by less-than-ideal access patterns.

So I've run this query to look at logical and physical reads for logical writes:

selectsql_handle, plan_handle,
total_physical_reads, last_physical_reads,
min_physical_reads, max_physical_reads,
total_logical_writes, last_logical_writes,
min_logical_writes, max_logical_writes,
total_logical_reads, last_logical_reads,
min_logical_reads, max_logical_reads
fromsys.dm_exec_query_stats

The question is, when can it be considered excessive?
Or can you just order the results by descending order and see if you can make improvements on the worst ones?

The same goes for this query for pageiolatch wait counters and times for indexes:
select database_id, object_id, index_id, partition_number, page_io_latch_wait_count, page_io_latch_wait_in_ms
from sys.dm_db_index_operational_stats (null,null,null,null)