is autovacuum recommended?

Hi,

Whenever i start a big action, like inserting millions of recs or doing a
large update, the autovacuum fires on top of that.
It has some adverse effects on performance when i need it most. More than
once a postgres service crashed on me because of it.
Sure, it had too little memory, but it wouldn't have happened if it wasn't
for the autovacuum.

Should ik keep autovacuum on, or is it better to run a script like:
vacuumdb -az (daily except one day)
vacuumdb -azf (once a week)

My database is growing, so really freeing up space isn't such an issue. What
I want is optimal performance.
Of course autovacuum is more generic, but for me i think the daily scheme
will be sufficient.
A connection told me it would be better to enable the autovacuum, because it
does more than the above script. Can anyone verify that?

Cheers,

WBL
--
"Patriotism is the conviction that your country is superior to all others
because you were born in it." -- George Bernard Shaw