slim filters for this lens

I'm about to buy a Canon 20D and an EF 28-135 f/3.5-5.6 IS USM and an EF 75-300 f/4-5.6 IS lenses and i'm not sure if I should spend the extra money for slim filters or not. I'm getting both UV and circular polarizing filters and i'm thinking i'll need at least a slim uv filter for the 28-135mm lens. Can anyone help? Also i've read that b&w is the way to go although hoya filters are looking more my price range, yet they are hard to clean cause of the multi coating. Heck, maybe b&w without multicoating is the way to go, i don't know. Any help is greaty appreciated. Thanks.

ive got all hoya filters and they are awesome. ive got a hoya pro1 uv and a s-hmc cir-pl on my 28-135. be sure to get multicoatings (the s-hmc versions for hoya, they should be the thin ones too), they make the glass pretty much invisible like theres no glass at all! and let 99% of the light in. if you get non multicoated, theres a glare on the glass. theres been another post on this, you can probably find kenko ones too, people say hoya, kenko are all the same, and their packaging is similar too. its up to you to decide to go thin or not. i love the thin double threaded ones. ive head that B+W is a good company to buy from too

I don't think there's any point going slim for those lenses, esp on a 1.6x camera. I doubt you'd get vignetting. Only extreme wide angles may require slim filters. Most slim filters like B+W don't have front threads, so you can't put your normal snap-on lens cap on the front.
If you really want thin filters, go for hoya pro 1's (or similar kenko ones) like kaitanium suggested, since they still have front threads despite being so thin. I've got a Hoya Pro 1 UV filter and a Kenko Pro1D C-pol for my 10-22mm. Many people report no vignetting with standard B+W F-pro mount filters even on the 10-22mm. I went for the Hoya and Kenko anyway because they were pretty cheap off e-bay and for a bit more re-assurance that I wouldn't get vignetting.

yep, about $80 can get you a kenko pro1 uv. i got my hoya pro1 off ebay for about $25 kakakaka =) yea i stole it.

Those lenses don't need slim filters.