Bananaman, if you are looking to get 265mhz out of a 2 gig set then XMS3200PT CAS2 almost certainly won't be quick enough. In fact XMS3500LL might not do the job. Then again even the best PC4000 sets are not gauranteed to get that fast (though most probably will).
If you are prepared to use a divider, which is nothing like the bugbear it used to be, then any PC3200 will probably get you to where you want to be in terms of Ghz. If you want to get good timings and keep your ram speed high then the XMS3500LL is a good choice. I get 240mhz at 2-3-3-6 and use a 166 divider to put me at 289 HTT. I was using a 133 divider but once i realised that the ram could take the jump it shaved nearly 3 mins off my Superpi 32m time. Though ram speed is not as important as it used to be, it still makes a big difference in my experiance and therefore i'd recommend something that can get you into that mid 200s range without silly voltage.