Denys sez:

>Never use addresses ending in 0, 1 or 255.

Actually, this needs to be qualified a bit further because of
the possibility of subnetting. In essence, you don't want to
use the subnet addresses with all bits off or all bits on. As
an example:

Assume your address is 192.168.001.xxx and your subnet mask
is 255.255.255.128 (that says that you're including the high
order bit of the rightmost octet as part of the network address
and not as part of the host address (e.g. you have two subnets
on 192.168.001 - subnet 0 and subnet 1).

Valid addresses would be 192.168.001.001 to 192.168.001.126 and
192.168.001.129 to 192.168.001.254 (or in essence, addresses 1-126
on the second sub-net). In binary:

11000000.10101000.00000001.x|xxxxxxx    IP Address
11111111.11111111.11111111.1|0000000    Mask
                           ||yyyyyyy    Node Address is 7 bits
                           |+-------    Avoid address with all bits
                   |              on or all bits off.
                Subnet address of 0 or 1.

Just dealing with the rightmost octet, we have two subnets: 0 and 1.
On subnet 0, the valid address range would be:
                  0|0000001     .001
                          0|1111110     .126
On subnet 1, the valid address range would be:
                  1|0000001     .129
                  1|1111110     .254

'Splain it? :-)