In terms of read/write speeds, recoverability, and power consumption (e.g. my HDD crashes and I need to have a lab take it apart) - what are the major differences between a 5400 and 7200 RPM drive?
How long is a piece of string!
The best thing you can do is to take a look at Harddrivebenchmark.net and directly compare the hard drives you are interested in.
As for power consumption, you have to look at the individual specification of the drive in question - the manufactures websites usually list this.
The reason I can not give RW speed is simply there is more to it than that - typically 7200RPM drives are faster, but, you also have to consider platter density as for example, the new mobile 1TB 5400RPM drive can outperform some 7200RPM drives for speed, under some circumstances.
There are several things to consider in addition to RPM.
RPM reduces what is called rotational latency. How long the hard drive takes to spin to the correct location.
Other issues to consider are the buffers on the drive (bigger is better), the disk to buffer speed (how fast can the reading take place), buffer to computer speed (SATA 3 is standard in many drives now).
As far as recoverability and power consumption, it depends on the drive not the RPM.