PG8.1 - Config file check

We are in the process of upgrading our 7.3.4 servers to 8.1, and I
wanted to have a sanity check ran against my config file.  Do you see
any issues with these configs?

Our servers are Dell 2650/2850's with dual processors and 8-12 GB memory.

postgresql.conf
listen_addresses = '*'          # what IP address(es) to listen on;
max_connections = 256
shared_buffers = 32768                  # min 16 or max_connections*2, 8KB each
max_prepared_transactions = 256         # can be 0 or more
work_mem = 4096                 # min 64, size in KB
maintenance_work_mem = 1048576          # min 1024, size in KB
max_fsm_pages = 8000000                 # min max_fsm_relations*16, 6 bytes each
max_fsm_relations = 5000                # min 100, ~70 bytes each
vacuum_cost_delay = 10                  # 0-1000 milliseconds
vacuum_cost_limit = 1000                        # 0-10000 credits
wal_buffers = 64                        # min 4, 8KB each
checkpoint_segments = 256               # in logfile segments, min 1, 16MB each
checkpoint_timeout = 1800               # range 30-3600, in seconds
effective_cache_size = 766980           # typically 8KB each
random_page_cost = 2                    # units are one sequential page fetch
constraint_exclusion = on
redirect_stderr = on                    # Enable capturing of stderr into log
log_directory = 'pg_log'                # Directory where log files are written
log_truncate_on_rotation = on           # If on, any existing log file
of the same
log_rotation_age = 1440                 # Automatic rotation of logfiles will
log_rotation_size = 0                   # Automatic rotation of logfiles will
log_min_duration_statement = 0          # -1 is disabled, 0 logs all statements
log_connections = on
log_disconnections = on
log_duration = on
log_line_prefix = '%d,%u,%p,%m,%c,%l,%s,%x,%i,' # Special values:
log_statement = 'all'                   # none, mod, ddl, all
stats_start_collector = on
stats_command_string = on
stats_block_level = on
stats_row_level = on
stats_reset_on_server_start = on
autovacuum = off                        # enable autovacuum subprocess?
lc_messages = 'C'                       # locale for system error message
lc_monetary = 'C'                       # locale for monetary formatting
lc_numeric = 'C'                        # locale for number formatting
lc_time = 'C'                           # locale for time formatting
add_missing_from = on


I have upped the following parameters to help speed up our
conversions, is there any issues leaving them set to these values
after our conversion to 8.1?
maintenance_work_mem to 1GB (1048576)
checkpoint_segements to 256
checkpoint_timeout to 1800 seconds (30 minutes)


Thanks,

Chris