I have WGS84 latitude and longitude for data points near Munich and I'd like to use a grid-type coordinate system, like the Ordnance Survey grids in Ireland or the UK.
What similar coordinate system do you recommend for Germany?
As markusN says you have to use a “official” coordinate system. In Germany, these two systems are used frequently:
In some federal states of Germany Gaus-Krueger is replaced by UTM. In other federal states the replacement of Gauss-Krueger by UTM will still take some time. In the federal state of Bavaria (where Munich is located) the replacement of Gauss-Krueger by UTM will not take place before 2016.
Basically you can use both systems in your maps:
You have coordinates in WGS. If you use UTM you do not have to make a transformation of the datum because UTM uses WGS too. This is an advantage of UTM. (You will find that the UTM-systems in Germany use ETRS 1989 as datum – not WGS 1984. But ETRS 1989 is virtually the same as WGS1984.) So, if you are using UTM, then you can bypass the whole issue of datum transformation. If you want to use UTM near Munich: Use UTM Zone 32 (EPSG 25832 - ETRS89 / UTM zone 32N)
If you use additional data from Bavarian local government: these data will often use Gauss-Krueger. Then perhaps it will be better to use Gauss-Krueger for your maps so that you can easy integrate these data. If you want to use Gauss-Krueger near Munich: Use Gauss-Krueger Zone 4 (EPSG 31468 - DHDN / 3-degree Gauss-Kruger zone 4)