Larger PATA 2.5" drives?

I've found an external 2.5" PATA drive enclosure which I'd forgotten I 
had (bought in error a while ago, meant to get the SATA version). It's 
a good one - Macally PHR-250CC USB 2.0/Firewire 400 with option for 
external power.

Now, the code name seems to be a bit of a giveaway to me but I thought 
I'd check - PATA 2.5" drives, can you get them in capacities larger 
than 250Gig and if so is it likely that they'll run fine inside here? 
Also, what's the tolerance on one of these, it would be good if I could 
just hook it up to my Mac Mini and leave it 'running' (by which I mean 
powered on 24/7 but spending the vast amount of its time spun down as 
the Mini is used purely as a media centre).

Or am I as well forgetting it and buying a Firewire/USB 2 SATA 
enclosure instead? Wondering what the price difference would be.


Cheers,
Ian