UDP is really great, but it also makes it extremely easy to spoof the source IP and flood your monitoring server with fake metrics. It's probably not a huge concern, but something to be aware of. See a blog post I wrote in the context of statsd/carbon[1]
<shameless plug> Also, if you're looking for a nice open-source front-end to graphite, take a look at Giraffe[2]. It also has a collectd plugin[3] </shameless plug>
[1]http://blog.gingerlime.com/2012/statsd-and-carbon-security/ [2]http://giraffe.kenhub.com/ [3]https://github.com/bflad/giraffe-collectd