Actually, asking for my portfolio is one of the most annoying things. The link to my portfolio was in my "Freelancer" post and you could take the domain from my email address and paste that in a browser address bar if you want to know who I am.
Also, the request said " It'd be great if in your reply, you could tell me experience / portfolio sites directly relevant to our requirements and setup". That requires thoughtfulness and time.
In both cases, it would depend on the nature of your work and the kind of client. If your work varies, you may want to highlight some areas of your portfolio to be more appropriate for a specific pitch. Similarly, a quote is rarely as simple as "you want a website/design/some sysadmin work, that'll be $price". You need to evaluate the task in order to give a sensible idea of your costs.
