Another issue with a sub-woofer is that producing adequate bass you can feel, may also disturb neighbors, kids, pets, etc. in your immediate living quarters! Bass you "feel" usually starts around 180Hz and the deeper you go, the more likely you are to rattle your surroundings (most buildings aren't built to contain such vibrations, and simply become more transparent to them, the deeper you go).
I'm very partial to the HSU Research sub's. They're very well designed and won't get you into thousands of pounds, euros or dollars (unless you really do want to "rattle" your neighbors!
). The other issue is generally transport. In order to generally produce deep acoustic bass, a LOT of air has to physically be moved. This means pretty hefty devices to do it efficiently. Stuff in the 60 to 150 pound (27 to 70 kg) weight range is pretty typical.
However, there is another option: a bass shaker!
These are much smaller devices physically mounted to your chair or couch that operate in roughly the same frequency range, but don't generate much acoustic energy. They simply vibrate your seat at the appropriate frequencies and levels. There are a number of these gadgets about from folks like Aura, Clark Synthesis, and ButtKicker. Combined with good "cans" (headphones) or sealed earphones, they provide a good "rollover" to "feeling the bass", when you don't have the option to use an acoustic sub-woofer. They do need a separate amplifier, but some come with even small D-Class amps that can certainly provide adequate power to "shake your booty"! Do a search for "bass shakers" on Google, and you'll get about 184,000 hits!
The major issue with shakers is achieving the correct balance between the shaker and the headphones/earphones so that when played back on a full range acoustic system, the balance is pretty much the same between the two listening "systems". In my experience, this is usually something the user develops through a lot of listening; especially to live performances, so you know what kind of balance to expect. (I have a set of Aura shakers mounted in my car!).
On top of providing bass "shaking", they also can provide a nice back massage on steady state tones too!
B.T.W. I'm also very partial to Etyomics ER-4 "earphones", as they provide the most balanced and accurate sound comparable to what's actually coming through to your ears in a live environment. These have become my on-site listening devices for recording classical music, and they really do provide a reference listening environment between your ears! They're also so small, that many folks don't realize you're wearing them until they try to talk with you, and you can't hear a word they're saying! These earphones truly isolate you from your surroundings so you can really focus on what you're listening to.
Hope this helps you out! Let us know what you decide!