Hoya usually has good price and decent quality. Both of your lenses use 52mm filter size, so you just need one filter.
If you want better quality, then can consider B + W, Heliopan or Singh Ray. Sing Ray has some combo filters that combines polarizer with other effects. These brands usually are more expensive.
The polarizing filter is the most used filter. There are other useful filters for special effects, eg. Neutral density filter, graduated ND filter, reverse graduated ND filter (for Sunset on the Horizon shots, a special filter by Singh Ray), color filters, and a number of other special effect filters.
Stacking filters can do multiple special effects, but will lower image quality, increase distortion and cause vignetting. A thin profile filter will reduce vignetting.
I have a Nikon D5000 with 18-55mm and 55mm f1/1.8 lens. Since I do a lot of outdoor and landscape photography, I am planning to buy a circular polorized lens. Can you please suggest the Polarized lens that goes with my camera lens.