I run event videography for various student groups on a college campus. We've been using three standard definition Panasonic AG-DVC3 cameras since I got the job, and we just recently added our first HD camera, a Panisonic AG-HMC40. Currently when doing a multicam setup we hook everything up over composite and feed it into our Panisonic WJ-MX50A mixer. We pull audio into that and then record over a RCA to firewire adapter onto a laptop. It's not the greatest setup, but it works most of the time.
One of our SD cams is starting to bite the dust, and we'd really like to replace it with another HD cam. Before I replace that camera though, I'd like some advice on an upgrade path. The ideal goal is to end up with some kind of HD mixing console so we can go all HD. I know the common standard is SDI or HD-SDI, so I'd like to know if it's worth it to invest in SDI compatible cameras or if HDMI-to-SDI connectors will work just as well.