What storage engine do I need - Mysql?
If you want a proper database then of the two you should go for innodb - it supports ACID transactions, referential integrity, and smaller granularity locking.

myISAM is faster in a number of read-only use cases but:


The lack of support for transaction safety can lead to corruption in multi-user situations where several updates happen at the same time unless you are very careful in your application design
The lack of foreign key support removes a valuable data integrity protection from your armoury
The fact the writes result in a full table lock can cause massive performance issues for use cases that involve much by way of insert and update operations.


innodb is currently the default selected if you do not specify a storage engine, unless you are running an old or badly configured instance of mysql (myisam used to be the default).

Update: as mentioned by akuzminsky in the comments, it may no longer be the case that myISAM is a better performer for any real world workload. A quick search for "innodb myisam benchmarks" seems to suggest this is the case.