I used to have the Thermaltake V9 and I did not like it from a build quality, ease of use, cable management, dust control or noisiness perspective. My environment is quite dusty, so some may forgive the V9 in that respect but my current Lian Li case deals with it much better. This is because I have setup the cooling to a positive pressure and it doesn't have a top fan. The V9 still has loads of other problems IMO, which might be worth suffering if the price is low enough.
I would suggest trying to find another case which is higher quality.
If you are not going to add a graphics card then you would be fine on a 300W PSU. If you do want the option to add a graphics card then I would go with the following (or the 550W version):
Rosewill Capstone 450W 80Plus Gold $60 http://www.newegg.com/Product/Product.aspx?Item=N82E168...
I might go with one of these anyway due to the build quality and efficiency being so high.
Wanting upgrade options is a legitimate reason to want a higher wattage PSU. You can run almost any build with a single graphics card with a high quality 550/600W unit.
The Rosewill Capstone 550W has a 45.5A 12V rail (546W) whereas the the Silverstone Strider Essential has a 42A 12V rail (504W). So the Rosewill unit is actually more powerful despite the smaller number on the label - the 12V rail rating is more important than the number on the label.
The Rosewill Capstone has superior performance; according to Jonnyguru reviews the Super Flower Golden Green platform (which the Rosewill Capstone series is based on) gets an average of 1% voltage regulation on the three main rails.
Ripple and noise suppression is excellent on the Golden Green platform - usually much less than half the spec on full load, altho the 750W review on JG showed that it was half the spec on full load; this is still an excellent result.
Build quality is also very high on the Golden Green platform. Efficiency is much higher on the Capstone vs Strider Essential, 80Plus Gold vs 80Plus efficiency (87-90-87 vs 80-80-80 percent efficient at 20-50-100 percent load levels).
The Golden Green platform is equivalent, if not superior, to the Seasonic X series which is used by Corsair AX units.
The only thing Capstones lack are modular cables. It really doesn't make any sense to me why someone would not go for one of the Rosewill Capstone units when they are so well priced.
I have read that some people are not a fan of Rosewill as a manufacturer, is this an issue in your mind? Is it worth the extra $10 that I would need to pay on NewEgg for the Rosewill over the SilverStone?
Rosewill aren't a manufacturer, they are a brand owned by Newegg. I completely understand that a lot of Rosewill branded PSUs are very bad and must be avoided. And that a lot of people have had problems with Rosewill in terms of customer service in the past in relation to the bad Rosewill units that they have bought.
However the actual manufacturer of the Rosewill Capstone series is Super Flower. In the past year or two Super Flower have been producing Golden Green based units for their own brand but also Kingwin (Lazer Gold, Lazer Platinum), NZXT (Hale90), Sentey (Golden Steel Power). They have all performed very well, the performances have if anything steadily been increasing. I would find it hard to believe that a lot of people have had problems with these units - I haven't looked for evidence one way or the other.
Personally I'd love any Super Flower Golden Green based units to be available in the UK, which they aren't.
So in terms of the quality of the units the Rosewill is absolutely worth $10 over the Silverstone. In terms of customer service/warranty etc that is a bit more abstract. Apparently the Capstones have a 5 year warranty which is nice. If Rosewill customer service is still bad then surely you would have the option of contacting Newegg instead. Finally, based on the quality of the Golden Green platform you shouldn't need to deal with customer service or warranties ever.