<p>I'm working on a projects which involves a lot of database writes, I'd say (<em>70% inserts and 30% reads</em>).  This ratio would also include updates which I consider to be one read and one write.  The reads can be dirty (e.g. I don't need 100% accurate information at the time of read).<br>
The task in question will be doing over 1 million database transactions an hour.  </p>

<p>I've read a bunch of stuff on the web about the differences between MyISAM and InnoDB, and MyISAM seems like the obvious choice to me for the particular database/tables that I'll be using for this task.  From what I seem to be reading, InnoDB is good if transactions are needed since row level locking is supported.</p>

<p>Does anybody have any experience with this type of load (or higher)?  Is MyISAM the way to go?</p>

I'm not a database expert, and I do not speak from experience. However:
MyISAM tables use table-level locking
. Based on your traffic estimates, you have close to 200 writes per second. With MyISAM,
only one of these could be in progress at any time
. You have to make sure that your hardware can keep up with these transaction to avoid being overrun, i.e., a single query can take no more than 5ms.
That suggests to me you would need a storage engine which supports row-level locking, i.e., InnoDB.
On the other hand, it should be fairly trivial to write a few simple scripts to simulate the load with each storage engine, then compare the results.