corruption in db. myisam bad? innodb good?

hi. database is myisam, 5.8Gb, 7mil records. recently had some corruption i think due to mysqld service failure. 10 tabes were crashed. question -- how can i prevent or minimize this? Will switching to innodb help? Will converting all my queries to transactions help? thanks. -- Tim H Berkeley

dump db without locking up the server

is there a safe way to dump/backup a live database without disrupting service? when i run mysqldump the whole server comes to a crawl and queries start taking 60+ seconds to complete. is there a way to make mysqldump run at low priority? worst case scenario is i miss the queries that took place