but not a HDC-HC3. The HC3 came out a few months after my HC1 - and is a more "consumer"-oriented version with fewer manual controls (no manual audio) and no external mic input - more on the Sony proprietary "active interface" in a moment).
This does not make it a "bad" camera - and actually I think it is a pretty good one. MiniDV, HDMI connector, LANC (this is really useful!) and switchable between 1080i hi def, 16:9 widescreen standard def and 4:3 (is always standard def) video recording (but do yourself a favor and don't do different formats on a single tape because importing that will require you to import to different "projects" by format).
On the Sony proprietary active interface - once upon a time, only Sony proprietary mics could be used - but whizkid454 found http://www.bhphotovideo.com/c/product/479976-REG/Sony_VMCK100_VMC_K100_Microphone_Adapter_Cable.html As far as I know, B&H is the only store that carries it. So, for manual audio control, add this plus something like the BeachTek XLR adapter mentioned previously and you are good to go.
The DCR-TRV30 is a great camcorder - but like I said, I am not comfortable buying this stuff used from folks I don't know - if you are, cool. The TRV30 has a real 1/8" mic-in jack - so that's great.
Heads up: The HC3 is a top-loader - the TRV30 is a bottom loader - for the miniDV tape. This is not a big deal is you are always handheld, but if you use a tripod, you need to either take the camera off the tripod (and the quick-release plate) or make/build a spacer so the camera sits high enough or otherwise away from the tripod mount. My HC1 is a bottom loader and that is one thing I don't like about it but I use a camera braket on the left for mounting an external mic and that, along with the BeachTek DXA-6 moves the camera high enough away from the tripod mount.
In either case, you will need to get a 4-pin camera side to 6-pin computer side FireWire400 cable to transfer/import the video you capture and most likely a high-capacity rechargable battery.
I wouldn't bother with the HDR-UX1. It is a DVD-based camcorder and not meant for capturing footage to be edited. If you decide to make this mistake, be aware that the hi-def video captured on DVD-based and hard drive based camcorders (from Sony and Panasonic and others) is compressed using AVCHD - and only iMovie from the the current iLife'08 and the current FinalCutPro 2 (not FinalCut Express) can deal with AVCHD-encoded video.
For external drives, I use these cases:
and get whatever big Ultra ATA (IDE) hard drive (Maxtor, Seagate, Western Digital, etc) happens to be on sale at Fry's. I noticed Fry's online does not seem to have these cases - but the stores typically have a few in stock. The reason I like these cases is because they do USB, FireWire400 and FireWire800... Your G5 does only FireWire400 (and USB - but you don't want to use USB for video editing), but if you get a new machine with FW800, it will be handy. Otherwise, any external drive (250 gig or larger) with a FW400 connecton will be just fine.
I understand "the local" can't compete on price... and I know price is really compelling... but remember that "the local" gives jobs to local people... your neighbors... maybe even you. And pays taxes which fund Police, Fire and other emergency services and builds roads and schools and all the other infrastructure we have - and need to maintain. And is a place to walk into to deal with a warm body if there are issues with what we bought... Sorry about the soapbox - and I know you are looking at, potentially, previously owned stuff which takes a lot of this off the table...