2way + 2way or 2way + 3way?

Spend as much money on the front components as possible.  The rears should be the last priority, in my opinion.  I generally prefer the sound of 2-way coaxial speakers to 3-way, but like the others said, it is the sound that matters.  Don't just order stuff blind off the internet. 

Many so-called "3-way" or even "4-way" speakers are actually not.  They are standard co-axials with a "super-tweeter" added for extended (and often way too bright) high-end response.  Many 3-way speakers actually use far cheaper components than 2-ways because with the super-tweeter the main tweeter can be of lesser quality.

And yes, the bass response has nothing to do with how many tweeters are stacked onto the woofer.

Most coaxials (2-way) use by far better quality speakers than 3-ways from the same company, in general.

Which in most cases means the woofer is the same.....

Nik, the reason I prefer speakers of like brand front and rear is for tone  / timbre matching. I find it easier and a more enjoyable listening experience listening to speakers that are very closely matched together. There is nothing worse that listening to your front speakers and then fading them to the rear speakers and going, man I like these ones better for their top end, too bad my front speakers did not do this. Tone and Timbre matching is much more crucial in a theatre type environment like a home theatre with digital surround, you wouldn't want that F-18 coming from the front to turn into a Cessna out of the rear.......what changed.... the type of speakers.