Hi and Welcome,
Your best options are to look for an A4000, A1200 or even an A600. The 3000 is a good machine but lacks AGA support and is a bit on the tight side for expantion unless you find a 3000Tower. The 1200 has alot of expantion add ons including many CPU excellorators available. as does the A4000(T) but is harder to find.
