I'd start off with a 225 and a pair of 90's initially. Then later on, add a pair of 225's to replace the 90's to match the centre, then move the 90's to the rear....long term will be a much better balanced and capable system.
I am also considering monitor audio radius speakers. I am looking at 2 radius 90's for the rear, 225 for the centre and a pair of 270's for the front. I'd also be interested in hearing anyone's views on these speakers and possibly a comparison to the b&w m1 speakers.
Kenko, What sub are using or considering to use with the radius speakers?
The Radius range is a strong range, particularly the 90's, 225's and 270's. They have been around a while now though and are probably due for an upgrade to keep up with the competition. If a combination of style and sound are needed, these should be most people's first choice along with the Quad L-ites.
If you need a small sub but aren't convinced by the MA sub, try Rel or MJ Acoustics.
The M1's are very good speakers, but i think the Quad and MA speakers are better, and their design will age better then the 'lifestyle' speakers most manufacturers have been releasing. The usual box loudspeaker will never date, and both the Quad and MA's come in some very nice finishes to match almost any decor.
But try all three, it's your choice when it comes to entering your pin number
I have the R90s and R225. I don't think the R90s are a good match for the R225. Ideally the drivers in the centre should match the front pair. The R180 is a better match for the r90s. If wall mounting, the R225s as fronts would be a perfect match for a centre R225. If you were going to use stands for the R90s, don't discount the R270. The R270 takes up less space than a speaker stand. I bought my R270s used from http://www.lintone.co.uk/ they still have a number available. They arrived in perfect condition.
I'm very happy with my R270s. I tried a lot of small speakers the R270s were the the best with music. The R270s take up less space and are cheaper than R90s + stands.