favourite pistol?

By far this question can be a bit challenging as you have to consider both sides, CT & T, and your economical base.

For pistol rounds I tend to use either the Glock or USP, depending on which side I am on.

For eco rounds I prefer either the P250 or Deagle, depending on what range I will be fighting.
Example: Fighting mirage mid T/ Defending A-site CT - I will use a Deagle
: Contact B or Fighting A ramp T/ Close ramp angle CT - I will use P250

Generally the more cash I have I will spend on the Deagle due to its capabilities of destroying enemies regardless of their armour or weapon.