I'm sure this topic has been discussed hundreds and hundreds of time, but i can't find anything specific with the search or the FAQ.
I have a 5mb/s down, 256kb/s up ADSL connection. Do i need to open some port on my router? What settings should I use on the Network Options? Slow-ADSL or Fast-ADSL? How many imput packets per second?

Can you lower your ping by configuring your router?

I beleive that the ping depends mainly on the speed of your internet connection. Might be that if other services are running on a PC behind the router that also up/download stuff to/from the internet that these then affect the ping too. But I doubt you can do anything about your ping just by configuring your router... anyone who knows better please feel free to correct me.

I know about packet bundling techniques that many DSL Providers use in Germany that also affect your ping - if you want to get rid of this, you will have to use the "fast path" option for your DSL contract, but that usually is available only for a higher price.

Don't use 100m-long cables or wifi I guess.

I don't use wifi and the router is one meter away from the PC.
Does the packets per second or the connection type settings have any impact on ping?

Ping is largely dependant on your distance from the server.

It's not a secret here that our internet services SUCK. Telefonica normally gives its clients about 10Mb/s, and reserves its fast connections to companies who pay a LOT of money for less-than-1Gb/s connections. There are a few, "independent" providers who give 20Mb/s to their normal clients, but since they have to end uo Telefonica's infrastructure, they put a lot of restrictions, like blocking P2P connections and giving routers with port opening disabled.