The client in it's current state is not a viable option for most people to run as a node in the not too far future. Both bandwidth and space issues will only intensify with further acceptance of Bitcoin. Thus either the client has to change with all that entails (such as developer decided rules changes) or more and more people will have to stop running a full node, when it's no longer viable for them.
That seems precisely reversed / backward.
It is only if YOU allow a change to the rules YOUR full node accepts which change permits bandwidth and space attacks which the current rules absolutely prevent that further acceptance of Bitcoin could lead to bandwidth and space issues beyond the scale your normal everyday class of equipment running your existing full node can handle.
That is precisely because the current rules absolutely, totally, utterly do NOT permit ANY block to be larger than one megabyte and even with massive massive uptake of ASICs spewing out blocks faster than one per ten minutes that can only result in so many gigabytes per year that your full node needs to be ready to handle, while whatever class of machine and connection you are already successfully using to run a full node continues to increase in power.
For example if your machine has the normal mass-retail-system disk drive, check how large a normal mass retail system disk drive is today compared to how large a normal mass retail system was one year ago, two years ago, and so on. Basically the price of a "normal consumer grade machine" tends to stay about the same while what it is capable of is more and more each time you go shopping for a normal consumer grade machine.
Even if every block is the absolute maximum size, and uptake of ASICs keeps accelerating so that the maximum rate of increase of difficulty cannot keep blocks from being spewed out at an average rate that never manages to reach the full ten minutes the software tries to target, there is still every reason to suppose that whatever class of machine you are running a full node on, the machines of that class, of whatever future time we project forwards in time to, will be well able to handle it all.
The danger is that someone will lure you into agreeing to download and use a node that permits larger blocks, or that targets a faster time between blocks, or both, so that the fastest speed largest possible blocks scale outpaces the rate at which the class of equipment you are accustomed to using to run your full node grows naturally in the course of your normal day to day obsoleting of your computer hardware.
As it is, if you do not get sucked into changing the crucial limits in the code, you can probably expect to handle your node with the hardware that is handling it now for another few years, by which time normal consumer machines will be so much more powerful than what you are currently using that simply putting in whatever connection and disk drive is then the norm should do you for another few, or maybe even several, years.
It is all very safe currently. It is only if the lure of putting more and more eggs in one basket, as in people onto one blockchain, lures you into hacking at those hard limits built into the current software that you are in danger.
If instead of butchering the existing system you deploy more and more blockchains (which your node's ability to serve as primary chain for the merged-mining of is already programmed in), as many blockchains can be deployed as adoption of the blockchain based currency concept might require in order that all people who need or desire to perform transactions on a blockchain get to do so.
Very likely the more they pay for their transactions the more ancient and respected and secured - and full to the brim every block - the specific chain their comfort level of fees affords them the use of will be. The elite might prefer to pay massive fees for the cachet of utilising the primary chain, the original bitcoin; others might feel the fee level of that chain is too high thus prefer to use the first secondary chain, and so on right down to those who use the latest and leastest chain that demand has caused by any given date to have been added to the panoply of merged mined chains (that the biggest, richest miners are able to mine every one of all at once despite the large number of them...)
Basically, putting the chain you use now out of your reach can pretty much only be done by luring you into hacking at the hard limits that are there to ensure it remains forever within your reach; if at some level of mass demand for blockchain based currency some folk feel it is not fair that there is no room for them on that chain, so what, plenty more chains can be created and all of them secured together using the merged mining ability that is already in the code.
Be very very very cautious of any attempt to make you vulnerable to untenable-for-you bandwidth and space problems that people unwilling to pay the price of the adoption rate pressure they try to apply to you might try to convince you to let yourself in for by changing the limits that currently protect you from any quantity of "adoption pressure" they might try to pressure you with. There is no need to let the masses force you out of "your own" chain, the chain you are already running a full node of. If they need more transactions per day, let them deploy more merged-mined chains...
-MarkM-