Best budget speakers for a Fisher X100 amp

I have a fisher x100 I just got up to snuff. I also have a technics TT.

The only speakers I have now are a set of Harmon Kardon HT10s that I found at a thrift store.

I want to pick up a decent set of speakers and so far I have been looking at

polk r30 - $100 a pair
polk r50 - $140 a pair
used cambridge sound works model 6 <$100 on ebay.

I also have decent wood working skills and could build a cabinet from plans. Is this a good way to go.

I would like to spend $200 or less on a pair of speakers that would suit this amp well.

I listen to classic rock and new alternative rock like radio head, white stripes, STP, etc.

Thanks alot