Zyrtec is without a doubt the most effective antihistamine in existence. Unfortunately, insurance no longer covers it in many cases, and it's close to $100 a month. Die, Blue Cross.
Claritin is what I use now, but it is nowhere near as effective.
Zyrtec essentially eliminated my allergies, Claritin merely lowers them. Benadryl would be great if it didn't make you fall asleep within 30 minutes. Sudafed helps with the congestion, but it's better to eliminate the cause... ever tried allergy shots? Neither have I
I'm thinking about looking into it though... I'm allergic to everything alive outside between August and December, most shedding dogs, and 99% of all cats.