Code line wrapping - how to handle long lines

I'm facing a particular line that is 153 characters long. Now, I tend to break things after 120 characters (of course, this is heavily dependent on where I am and the local conventions.) But to be honest, everywhere I break the line just makes it look bad. So I'm looking for some ideas on what I should do for it.

Here's the line:

private static final Map<Class<? extends Persistent>, PersistentHelper> class2helper = new HashMap<Class<? extends Persistent>, PersistentHelper>();

I'm open to both ideas about how/where to break the line (and why), as well as ways to shorten the line itself.

We're not a Java shop, and there aren't local conventions for this sort of thing, or obviously I would simply follow them.

Thanks!