Any conversion that you perform on the native .mts video files is going to take time which is the exact opposite of speeding up your HD workflow. The obvious answer is to use a system and software platform (CS4.1) capable of editing the native files so you don't have to do any conversion. Conversion really defeats the whole point of shooting tapeless, in that you are trying to minimize the number of steps from acquisition to editing to delivery. Conversion just adds one more step.
If you are using a Panasonic AVCCAM video camera, then you can use the MainConcept AVCHD to P2 DVCPRO HD Transcoder, which is free to use and converts your .mts video clips to intraframe P2 .mxf video files which will be much easier for you to edit. I can only assume since you are on this Forum that you are using Premiere Pro CS4, in which case the latest 4.1 update provides dramatic improvements in AVCHD editing performance.
Another way you could do it, although more expensive is to use a Cineform product.
I have a SONY Handycam which will accept a 16GB memory chip and use a relatively outdated machine (Ie quad core AMD with xppro) and Cineform Prospect HD along with Premiere Pro CS3.
Prospect has a capture, conversion module (HD Link), which won't capture AVCHD files, but if I record the HD video to the chip instead of the hard drive of the camera, I can then insert the chip into a USB chip reader and the HD Link will directly convert the AVCHD files from the chip into Cineform .AVI files and save them onto the computer HD which can then be edited in CS3.
There is a minor problem with the alpha channel which can be worked around using quicktime files.
I've never looked at the Cineform product Neo Scene HD, but it may be cheaper. I'm not sure if Neo Scene converts the AVCHD files.
Thanks a lot for your help.