Strategy to improve Backup speed on slower network

I was thinking of setting the desktop as backup server. The downside is that virtually all of the laptop are 100-base-T, so it's not so easy to upgrade to Gigabit. When I did a simple benchmark, I notice that:

801.11g - 2.36 MB/s
802.11n - 5 MB/s
100-Base-T 9 MB/s

If I upgrade to 1000baseT, I could probably at least double the rate of teh 100-base-T. Since the drives continues to get bigger, it now takes an entire night to backup something. What can I do to get backup working on the slow bandwidth?

One idea is to turn off verify backup. This tends to help a lot, but how much reliability am I giving up for speed?

What about increment vs differential?

If I increase compression to the max, would this help or not really (since it will take longer to decode or encode)?

Thanks

Paul