Hostels or Home Owners? London/Amsterdam/Rome beds for 5/..

(Reposted from rec.travel.europe)

I'm getting a bit bleary eyed nightly reading wildly differing accounts
of the same Hostels posted as reviews on a number of related
websites...what/who to believe???

Can anyone please offer some personal recs for cheap (less than $25-30
US average per on 3-4 days booking) centrally located accommodations.
A dorm situation I don't mind; Animal House filth and mentality I DO
mind... I'm 48 where the issue applies and traveling alone; savvy and
imposing enough personal security is less an issue than baggage thievery
when I'm not around, so a good lock-up is important. Some kitchen
privilege would be nice but 'free internet and breakfast' (our own bar
sounds like trouble...) is low on importance.

Of the few acquaintances I have that traveled Europe on the cheap (most
20 years ago) some have mentioned that they found their best places to
stay in privately offered rooms, transaction occurring privately near
tourist offices and air/train stations. Any comments on personal
experience here? I would find it a bit daunting however to arrive in
these cities without any notion as to where I'd be sleeping that
night... Therefore, is there any way to hook-up such deals in advance;
possibly even getting references from others who've used them? TIA

Tim K