Re: Changing speakers in a low watt combo?
"Low-watt combos" is a strange market segment. Some low-watt-combos are built for people who believe that cranked-up low-power amps give the best tone and buy nice amps built specifically for this purpose. These are mostly boutique amps.
Another part of this group is simply "cheap tube amps". There are many models out there that are designed to make a tube amp as affordable as possible. You could argue that the "all tube" label is more important than tone - components are certainly selected primarily selected to meet the price point, and the speaker is one of the major contributors to the amp's overall cost. Good examples of this kind of amp are the Fender Blues Junior and the new Ibanez line of small tube amps (Valve King?).
Many people have found that re-fitting these amps with a quality speaker helps a lot. So, when corners have been cut, the speaker is an easy way to make a major improvement. ANY good speaker would be a step up, even moreso if you take the time to find a good speaker that's suited to you taste and playing style.
Back in the boutique world, the builders put a lot of effort into making sure the speaker is matched to the amp. Chances are the stock speaker is a pretty good one. But, it may not be suited to your particular style, so finding a speaker that suits your taste could also be an improvement.
The problem is that it's entirely possible to spend big bucks on a speaker that sounds awful to you. If possible, try out as many speakers as you can with your amp - borrow friend's cabinets, plug your amp into other combos' speakers, swap speakers around, whatever. If you can't do that, then read reviews, post your style/preferences on the forum and ask for suggestions, etc. Do some research, make an informed choice, and a speaker swap can be the biggest bang for your buck/effort that you can get.