1080i AVCHD to what file type?

[hollywood10s]

I am recording videos for my website using a camcorder that records to AVCHD file type. I am using vegas or ulead video studio 11 to edit them. What file type should I export these AVCHD to after I'm done editing them? My choices are HDV 1080i (1440x1080) HDV 720p (1280x720), or HD-DVD 1080i (1920x1080) I am then encodeing these files using Megui get the smallest, highest quality file as possible to be viewed using the jw player through flash. Are there any advantages to one of the file types above over another for the purpose that I'm going to be using them in my website? I figure the 720p will be a smaller file than the 1080i when I load it into Megui, but I dont know if the final file after being encoded will be any different files size or quality wise. Also the 1080i has to be interlaced and the 720p doesnt, again are there any advantages to one methode or the other? These video are mostly of fishing so the Megui has to encode moving water and some movement. Other videos are mostly still video and they dont require as much. Another thing when I export to 1080i the resolution is 1440x1080, but I want it to be viewed on my website at the correct widecreen resolution (either 1280x720 or 1920x1080 ie mod16). Is my quality going to suffer loading a 1440x1080 file and downsizing it to 1280x720 or (720x405 that could be upscaled in fullscreen to 1280x720)? Let me know what you guys think the best file type is to export to when encoding into Megui. Thanks again for the help.

Chad