Is it good to make a separate partition for /boot?

This is a holdover from "ye olde tymes" when machines had trouble addressing large hard drives. The idea behind the /boot partition was to make the partition always accessible to any machine that the drive was plugged into. If the machine could get to the start of the drive (lower cylinder numbers) then it could bootstrap the system; from there the linux kernel would be able to bypass the BIOS boot restriction and work around the problem. As modern machines have lifted that restriction, there is no longer a fixed need for /boot to be separate, unless you require additional processing of the other partitions, such as encryption or file systems that are not natively recognized by the bootloader.

Technically, you can get away with a single partition and be just fine, provided that you are not using really really old hardware (pre-1998 or so).

If you do decide to use a separate partition, just be sure to give it adequate room, say 200mb of space. That will be more than enough for several kernel upgrades (which consume several megs each time). If /boot starts to fill up, remove older kernels that you don't use and adjust your bootloader to recognize this fact.

One reason for having a /boot partition is that it allows for things like encrypted /, where the kernel and initrd are loaded from an unencrypted partition and then used to mount the encrypted root partition containing the operating system. It shouldn't matter for general usage however.

Adding a comment from Riccardo Murri:

There are also historical reasons for having a separate /boot: in older times, the BIOS could only access part of a large disk, so all files needed by the OS bootloader had to be kept in the BIOS-accessible zone. Hence a separate /boot partition. This does no longer apply, though

The main reason for the major enterprisey distro's like Red Hat and I think Suse to use a separate /boot is that they use LVM by default and Grub cannot be used to boot from LVM. It is that simple.

So if you want to use LVM, and that is a boon, you use a separate /boot. Personally, I think it is good practice to use both LVM and separate partitions for a host of things, like /var, /boot, /home and /tmp and even /usr on servers, for example in order to protect your root filesystem or data partitions from getting full.