It doesn't sound like we have a load of Final Cut Pro folks on the board (hard to tell),
Are you implying there is something else other than Macs and Final Cut? I have never heard of that myself (Wagsy in case you see this, I know PCs and Edius
)
but I'm wondering if those of you using both the HDV system and FCP can help me set up a better workflow on my iMac. I bought it custom, so I've upgraded the RAM and the video card beyond what comes standard.
Heinrichs, where you at, bro? *cough* 
Some of this varies depending on the machines and time frames and space available, I change things up slightly depending on which Mac I am using and what I have with me (sometimes I bring a SATA RAID on a trip with a MacBook Pro Duo, sometimes I have an iBook because I do not want to carry things, sometimes I am in front of the Tower with my real monitor and all my hard drives, so results will vary
)
People argue this back and forth all the time as to the "best" way to work with HDV in FCP - there is the theory and the practical. Practically speaking HDV is not easy to work with because of the horsepower needed, and if you can edit in a format that is easy on your machine and meets your goals for output, such as Web or DVD, that is a good approach to consider and use.
One way is to convert the material to DV Anamorphic - it is very easy to work with since it takes up less room then other Codecs and requires less horsepower and data rates compared to other Codecs.
Then use Media Manager to create an HDV timeline of the DVD Anamorphic sequence, re-attach the HDV media, set the timeline to an Uncompressed Codec, such as 8-Bit, clear all render files and export the timeline. Depending on your computer, the length of the movie and other variables, while it is exporting go grab some coffee or a nap or see a movie.
I know it sounds like alot, but actually pretty easy once you get used to it, does a good overall job (for DVD and Web it is fine).
There are some other approaches/techniques to consider or explore, such as getting the HDV to DVD and an approach is here.
http://www3.telus.net/bonsai/Welcome.html
Worth looking at.
HTH