If you want help picking out parts whether its an entire system or just parts or to upgrade or anything really, make sure to specify the following information:
1. Your budget. This is the most (literally) limiting factor. You dont need to nail it down to an exact number of dollars and cents: a rough estimate is more than sufficient. UNLESS OTHERWISE SPECIFIED, monetary values are understood to be in USD.
2. The purpose: what do you plan to use the system/component for? This will help the rest of us who might respond to be able to tailor a response to a specific requirement you might have.