Aron - hope this is udeful - I'm no expert

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Each of your quastions has good coverage on this forum.
Would any experts please advise me as whats the best bang for the buck projector on the market now and the screen to go with it for a 13x15 room?
An impossible question as there are those who will tell you that an $12k PJ like the Marantz S2 is better bang for the buck than the $5k Infocus 5700. You have to see them. As for screen size, that's a whoe different subject. There are several recent threads with 4:3 and 16;9 advocates both making good points.
Are the Sharp 9000 easy to setup and suitable for beginners?
generally, modern digital PJs are easy to get to 90% performance within a few minutes. Extracting that next bit is more challenging and may involve help from this forum or external help.
How does the picture quality of a DLP projector compare to my Panasonic 34 widescreen HDTV for watching mostly DVDs?
Only you can answer this because I don't know your TV and how you see it. The image will be bigger!
Do I need to hire any experts to calibrate or install all the hardware?
Again, this depends on what you are trying to do and your ability. KraikK for example ahs done the most amazing self built theater on his own. It's better than many pro efforts.
Rob