I'm with kYutobi on this one; provided you're not going to readily run out of IP addresses, then use /24 subnets; they can never be considered too big, as broadcast domains and just because they're really easy to work with, with the third octet letting you see, very simply, whether two addresses are really in the same subnet.
These days you'd probably get away with /23 or even /22, but as soon as you started getting some kind of intermittent performance type issues, there'd be that nagging doubt as to whether broadcast/L2 multicast levels might be coming into play, which take time to allay.
One exception to this, in a big network, would be if you ever need 'transit VLANs' or similar, in which case I'd go for /29. /30 is always tempting, in those circumstances, but if you ever wanted to insert a device between - say for management, monitoring or traffic manipulation purposes - you'd be stuffed, but /29 is still pretty address-efficient.
