Coffee capsule machines are certainly a convenient way to get your caffiene fix. However, they're not the most environmentally friendly gadgets, given that each capsule is for single use. You can avoid that problem by hacking the capsules and re-using them, but does it make sense?
I first came across the concept of re-using coffee capsules back when I reviewed the ALDI Expressi
Since that review, the Expressi has mostly sat idle, although it did experience a brief flurry of usage when ALDI started selling its Chocolat capsules (no prizes for guessing what kind of hot beverage they contain).
ALDI's Expressi is just a slightly rebadged K-Fee machine, and there are lots of other models on the market, most of which can also have their capsules hacked. If you have one of the less common Tchibo machines, this blog post at Cheap As Chips covers how to re-use its capsules. This Instructables guide covers re-using Nespresso pods, although it's apparently also possible to buy third party "reusable" pods as well.
I appreciate the fact that reusing a capsule has some environmental benefits, and that it allows you to experiment with your own blends and flavours. It could also save you money, though that depends on how pricey a blend you use for the refill.
Still, surely the benefit of a capsule based system lies in convenience, which is exactly what you're sacrificing by taking the time to carefully pack and re-line capsules every time you want a cup of coffee. After only a short time, wouldn't it make more sense just to make actual coffee?