I use Optimism, it's a free program that also syncs with your free online account, has charts graphs, highly configurable for personal needs. I love it and highly recommend it.

Now as for charting, it's definitely a good thing! Even if you lose interest in recording daily and have lapses of months with no entries, it's beneficial! It helps you see patterns and trends. I been doing it for over a year now, wish I started sooner! I discovered that I got depressed around the same time last year and seen how long it lasted and can read my daily notes from them, it's cool seeing your mood swings on a graph too.

Seriously, Optimism has been one of the best tools I've come across.