Picasa is great for ease of use and I think you can upload any image size (?). The upload from picasa2 is v. low hassle.
Storage-wise it is a bit annoying: I currently get 1GB storage for photos and 7GB for my email. Amount for email keeps growing - for picasa has not changed much.
I can upgrade to 10GB shared across mail and picasa for $20 a year - which is hardly any different than I have now except I get to use spare email space for photos.
40GB (shared mail + picasa) is $75 a year - not cheap!
Of the various alternatives I've seen the best looking (imho) is
smugmug Unlimited storage, $40 a year, nice interface.
Cheapest? = Flickr upgrade to unlimited storage for $25 a year. I find flickr a bit annoying and have had trouble with their upload tool crashing out when I have set it to upload a lot of images - but that is probably my incompetence.
Dont know how this compares to buying your own webspace [or using the free space we all get with a broadband deal] and using e.g. jalbum to display photos.
rc