Major problem with online storage systems. Yes, you can store it online. No, you cannot access it from any corner of the world - the entire planet is not covered under broadband internet services yet, and it'd be a real pain to try and download a 5gb file on a 56k connection. I also question the "it is so simple" - some of the online storage systems are a pain to use.
That said, online storage is extremely useful in some instances, but I question the "you don't have to take your laptop everywhere just cause there's important data on it" argument. I just picked up 2 8gb flash drives from the local Best Buy for $8 each. I don't any 8gb files that need to be transferred, but honestly I have them more for security - if all you need is the data, and not a way to read it, a flash drive is a perfectly viable alternative, comes in a ton of different capacities, and generally speaking can be bought when on a good deal for a really cheap amount (best buy also had 16gb's for $16, but I don't have any files that'd require a solid chunk of storage like this).
Depending on the situation, you might indeed have to take your laptop anyways - imagine if you're going somewhere that has no internet or slow internet. Can't get to the cloud from there. What if where you're going doesn't actually HAVE a system for reading the data? What if you don't trust their network's security with your password? You'll be hauling the laptop again.
My personal thinking on it in a nutshell? Great idea, don't rely on it. ALWAYS have a backup plan - mine's an 8gb flash drive, and if it's really important, a DVD-R in a nice cloth case.
Off subject, OP was a spambot (spam link removed along with pruning their history); it's a valid discussion point to start on however, so I'm leaving the thread in this instance.