A bit of this depends on how/where you are going to use this Video. For DVD-Video, then the same DV-AVI Type II w/ 48KHz 16-bit PCM/WAV Audio will be good.
If you are going to transport this file to another application, then look into the Lagarith CODEC. It is lossless and will retain the greatest quality, with the trade off of larger file sizes. Also, make sure that the other app. can use the Lagarith CODEC.
Premiere PRO CS4 can export a lot bigger files then 3gb without problem. I hope your disk is not formated to FAT32 which has a file size limitations of 3gb.
You can export video from premiere couple ways. Using Media Encoder, using Flash or dynamic link it to Encore and burn dvd there. Using Dynamic link from time line to Encore and transcoding it to dvd is the most efficient way of exporting video from premiere.
DVD usually can hold one hour of transcoded SD video. So if you have 25 minuets of your video it shout take little more then half of the DVD disk when it transcoded with highest quality 8mbps
I do not see what version of PrPro you are using, but for going to a DVD-Video, you will use an authoring app., like Adobe Encore. It can Import the DV-AVI Type II files, and will then Transcode these to a much smaller size via MPEG-2, the file type of a DVD-Video. Your Duration will easily fit onto a DVD-5 with maximum quality.
It that is your goal for a delivery scheme, it will be very simple.
PS - Also comment on the formatting of your HDD's as per a question upthread. You will want NTSF, and NOT FAT-32.