$70 rebate check is burning a hole in my pocket.

[Quicklabs]

When I bought my memory cards, they had a great deal going for the rebate, which I received yesterday.
I'm going to use it for some filters.
I'm needing a 72mm filter for my 18-200 lens and I'll need a 77mm for the wide angle which is in my future.
I use the 18-200 most of the time.
Would you recommend buying a 77mm and a step up ring for the 18-200 lens or a 72 mm and a step down ring for the wide angle? (Or is the up/down reversed?)
Thanks!
SInce I also need a camera bag and a tripod, I have a feeling that the rebate check is going to end up costing me a few hundred bucks. :

 

[YesDear]

I have the 18-200 and purchased a step up ring to 77mm. Now I already have a circular polarizer for a 70-200. 72 is an off size and 77 is far more standard. I also purchased a 77mm Nikon lens cap so it all matched.

I am sure I will get conversation about this comment, but I do not spend a great amount of money on the 1A or UV for the lens, but did spend good money on a polarizer.

 

[saturndb]

I have the same setup as yesdear. bought a step up ring, also ken rockwell talks about filters and a step up rigng on his site.
check this link:
http://www.kenrockwell.com/tech/filters.htm

 

[jann1033]

what kind of filter? cp or uv? if uv do you have a hood for your lens? if so i'd skip the filter and get the bag....if cp i'd get the bigger and the step up ring.( what i did with my 67/72 or get a cokin grad nd set up which also uses a step up ring to get the whatever size you need ( would probably be a bout the 70 by the time you get what you need) the holder you can get for wide angle lenses..otherwise i think you sometimes have difficulty with vignetting and wide angles http://www.geocities.com/cokinfiltersystem/howitworks.htm
i think all in all the cokin might end up being less expensive since the filters can be interchanged and to be honest, i sometimes just hold the filter up in front of whatever lens i am using