I have got the VPS i wantd in my budget they offer 128MB Ram I am plannin to use 2 sites a forum where debugging shows memory used is 5MB and a wordpress blog where it shows 18MB if i get 1000+ visitors per day will it be sufficient?
Must have meant 128 MB of memory. But that would only = 256 MB of memory, which isn't enough, IMO. You should at least have 512 MB of memory if you're going to be using cPanel with a VPS.
A forum uses a lot of memory, I think something with 512MB is more suitable... Even something with at least 256.
256mb is a minimum for apache+php as base for wordpress... But with 256Mb you have to optimize configuration in order to have more or less good performance.
Give Webmin a try instead of using cPanel. And if you are experienced, then you won't even need a control panel.