30 seconds is a reasonable target - however, this assumes a high performance network with no bottlenecks (e.g. gbit backbone, 100Mbit switched, multiple subnets/VLANs to minimise collision/broadcast traffic). Introduce wireless and 2 minutes is more likely.
For boot times make sure you only have the services you need running, in theory Xp should boot in under 30 seconds, however under RM the client must obtain a license from the server so that will probably take a while. From login prompt to start menu, and again on an ideal network should be about 4 seconds.
Other things to consider - virus/worm/spyware infection, DNS issues, overly large profiles (like >2Mb), RM CC use...
Also who put your network in? I cant go into this for legal issues, but if an RM contractor such as Networx put it in, get it audited by an outside contractor such as GGR (the ones I've used) and in the meantime use ntop to give you at least an idea about the level of latency. Regards, Ben