Update:
Pay attention to the Final Release of NetBeans 6.5.
According to the Roadmap, the NetBeans Developers released a official beta (6.5).
Download:
http://bits.netbeans.org/download/6.5/m1/
Looks very stable to me (i use only the ruby package), so i can recommend the download.
Hava a look at the Feature List:
http://wiki.netbeans.org/NB65EngineeringPlan#section-NB65EngineeringPlan-FeatureDetail
