Best Answer - Chosen by the Asker
"Chcę pisać list"- the verb "pisać" is in the imperfect form, which means that you want to write a letter, but it takes some time and you don't know when it'll be finished.
On the other hand "chcę napisać list" means that you are going to finish the job before a certain, say, deadline. This is because "napisać" is a perfect form of the "pisać" verb.
Some more examples:
- "w przyszłym roku uczę się polskiego"- I am gonna learn polish next year (but it will be a continuous process without any clear aim or deadline),
- "w przyszłym roku nauczę się polskiego"- I am gonna learn polish next year (to be able to speak fluently- the aim is clear here and it will be finished till the end of the next year)
- "jutro sprzątam mój pokój" - I'll clean my room tomorrow (it will take time and I am not sure if I can clean it up)
- "jutro posprzątam mój pokój" - I'll clean up my room tomorrow (it's gonna be really clean)
To answer your question which form of verb is right- it depends on what you'd like to say. To express continuity you use the imperfect form of a verb, otherwise use the perfect form.
