I would like to buy a studio microphone that sounds great ( I need professionnal quality), which microphone should I choose, which model? ( I know that Samson and Studio Project have cheap mikes, but I don't know if they sound great)
I also would like to know which microphone preamp I should buy ( Not too expensive)

I have a Tascam portastudio, but when I record guitars, it doesn't sound great, it's flat. What sould I do to have a good guitar sound? (Do I need to buy something like Line 6 Pod, or other?)

Many thanks for your help