I'm an avid photographer, although my main photo collection resides on my iMac w/2TB drive, and my MBP is just a secondary machine and only carries a copy and subset of that data. but my photo backup strategy should still apply to your case using your MacBook.
if your data(photos/video) are important to you, I would no matter what make sure you have at least one backup on external media. large hard drives are pretty cheap these days, so there's no excuse not to get one. An external drive is even more important if your laptop is your main machine - every once in a while on the news there's some story of a person having their laptop stolen out of their parked car with their only copy of all their treasured newborn baby or wedding photos, pleading for the thief to return their photos (hint: there's at least 2 mistakes made by those people!)
actually, I have a full Time Machine backup on my main iMac, plus I do a periodic full bootable clone using SuperDuper in case of emergency (having a bootable clone has saved the day for me before). But because I want to keep a full separate archive of all my photos, I also have a 3rd external drive which I use with SuperDuper to ONLY backup my photo folders. This photo archive hard drive is like my modern-day "shoebox" of photos.
The TM drive is FW800 for speed, but I use USB2.0 drives for the bootable clone and photo archive drive since they're cheaper and they're not being accessed as frequently. The bootable clone and photo archive drive I store separately from my Mac in case of some disaster/theft/etc and I run the SuperDuper backup to those perhaps every few weeks.
if your photo/video collection is too large for your laptop, you could manually copy them to an external photo archive disk then use this external drive as your "master" copy. then only keep a copy of more recent photos on your laptop's smaller hard drive. then keep the external drive at home for safekeeping -- I don't want to hear about you on the news :)
personally I would not want to use storage in the cloud as my "master" copy of my photos - I have too many GBs of photos and it would take too long to restore them all should some disaster strike my machine. Also I would worry about long term reliability if it weren't a large well funded company (some of those smaller startup online photo sites have gone belly up in the past!). but some people seem to be comfortable doing so, I guess it depends on the volume of data and how important it is for you to have control over your own master copy of data. even if cloud storage worked perfectly I think I would still only rely on it as a 2nd copy of my photos.
I do use Mobile Me, but for me it is just to use as online gallery to share with others and for the other great syncing features between all my Macs and iPhone and Back to My Mac. I don't rely on that as my "master" copy of photos. likewise with sites like Flikr or others, great for sharing but not a solution to archiving large photo collections, IMO.
p.s. as mayer already suggested, step 1 is to upgrade your internal hard drive to something larger. but then seriously consider adding at least 1 backup external drive.