Ok: wrt ADSL and static IP addresses: true enough (unless you can find a cable provider that does static, I'm not aware of any), but anything that *requires* static IP probably shouldn't be on the end of an ADSL line anyway. There are plenty of dynamic dns services out there, which resolve this particular problem neatly.
Oh, I dunno. ADSL is stable enough to host things like secondary DNSs, secondary mail servers and that kind of thing. This gives me the ability to have secondary services of this type that I own and control without the need to pay expensive hosting charges. Mine has been up for months and seems extremely stable (he says, tempting fate :-).
On the dynamic DNS front, it can be a pain if (for instance) you want the firewall in your main hosting centre to trust connections coming from your home office, but your IP address keeps changing. This said, there are solutions to this problem, such as using VPN connectivity instead of trust arrangements (which adds the benefit of encryption, of course).
D.