What is the difference between Latitude and other choices?
Latitude is the line focused at heavy business users. Better construction and good technology. More or less, the flagship line. Intel Core-i5 and Core-i7 processors.
Inspiron is aimed at home users. Lesser construction quality, but decent tech. Intel Core-14 and Core-15 processors.
Vostro is aimed at low end business users who need good construction but lower performance. Older tech standards, but robust. Older Core2-Duo processors.
Latitude has a clunky keyboard and mouse.
Go with the Studio.