There are no 160GB longitudinal drives (Fujitsu has their 4.2k rpm 200GB, but that's because they use 3 platters instead of the usual 1 or 2, and therefore it's thicker than the required 9.5mm drive height that would fit into a MB/MBP), they are all 2 platter designs using perp. recording tech. Highest capacity 2 platter long. rec. tech in 2 platter design is 120GB. No, 7.2k drives will still 'feel' a little more responsive in general use, but 5.4k perp. drive are close in STR (sustained transfer rates, which are important for video/audio recording).
Get a 160GB 5.4k rpm drive; Seagate was 1st with these (Hitachi shipped the 1st SATA version however), and now WD has one, Fujitsu has 'announced' one, not sure about Toshiba or Samsung. Then come Spring 2007?, swap out that 5.4k 160GB for a Seagates Momentus 7200.2 7.2k rpm 160GB perp. tech. drive.